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■: ■ V -
AGRICDLTDRAL TEXT-BOOK FOR SCHOOLS."^ '^'
FIRST PRINCIPLES
. OF
AGRICULTURE.
BY
PROFESSOR TANNER, F.C.S.,
WITH INTRODtlCTIOK, EXPLANATORT OP THE FIRST PRINCIPLES OFCHEMISTRT AND
THE SYSTEM OF CHEMICAL NOMF.NCLATURB,
BY PROFESSOR LAWSON, Ph.D., Ll.B., F.I.C.
Prescribed by the Council of Public instruction for use in the Public School
of Nova Scstia.
HALIFAX:
A. & W. MAOKINLAY.
1880.
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Kntered
accor(lin>{ to Act ot Parliameiit of Canada,
in the
year 1880.
By a. k W.
Mackinlay,
lu tlie ottioe of tlio MiniHtor
of Agriculture,
at Ottawa.
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INTRODUCTION.
The Art of Agriculture is based upon the Science of
Chemistry. Thi;re can be no intelligent cultivation of
the soil \<'ithout some knowledge of the leading princi-
ples of chemical science. The acfj^uisition of such
knowledge becomes possible, and indeed easy, when
the pupil is mf\de acquainted with the peculiarities of
language and the nature of the formula) and equations
employed by chemists. An acquaintance with these
modes of expression is required for the purpose of
convoying chemical ideas with the necessary precision,
and no attempt should be made to teach chemistry
without their use.
The rules for the formation of Chemical Terms and
Symbols, and for the construction of formulae and
chemicid equations, are exceedingly simple ; and chemi-
cal language and notation, instead of interposing diffi-
culties in tlio pupil's way (as is feared by many
persons), on tl" ".ontrary, render clear and easily com-
prehensible whai would otherwise appear obscure and
confused. This is the sole reason why they are used.
The work of the Agriculturist is to convert matter
in the soil, which would otherwise be useless to man,
into useful crops, and to convert the whole, or a por-
tion, of such crops, into flesh, wool, butter, and other
animal products. The processes by which these con-
versions are accomplished depend upon chemical laws,
according to which all changes of matter take place.
Matter, or material, of whatever nature or aspect, is
either (1) Simph', consisting of one kind and not
capable of yielding any other, or (2) Cnriiponnd, that
is, made up of two or more other kinds of matter
which are simple. When a substance consists of only
one kind of matter, it is said to bo elementary, this
ultimate form of matter is called an Element. The
iv.
INTRODUCTION,
number of such Elements discovered up to the present
time (February, 1880,) is eighty, of which sixty-four
are Metals and sixteen Non-Metallic Elements, or, as
they are sometimes called, Metalloids. The metals are
mostly solid bodies at ordinary temperatures, one
(Mercury) is liquid, and many of them can be convert-
ed into gases by heat. Certain of the non-metallic
elements, Carbon, Sulphur, Phosphorus, &c., are like-
wise solid, one (IJromine) is liquid, and several
(Hydrogen, Oxygen, Nitrogen, Chlorine) are gaseous
at ordinary temperatures. Those that are solid or
liquid can mostly be converted into gases by heat,
and those that are gaseous can be condensed by pres-
sure and lowering of temperature into liquids or solids.
This difference of condition, whether the elements be
solid, liquid or gaseous, does not necessarily represent
a chemical difference.
Chemically the Elements may exist in two condi-
tions, (I) In the free state, (2) Chemically combined.
The atmosphere consists mainly of two gaseous Ele-
ments, Nitrogen and Oxygen, mixed mechanically; in
the proportion of about four parts of the former to one
of the latter. When thus mixed each Element retains its
own properties unimpaired except by dilution. It is
quite otherwise when the Elements combine chemically.
Two or more Elements chemically combined form a
Chemical Compound. In such a compound certain
properties of the Elements composing it are no longer
displayed. The Elements, when they unite, counteract
each other's activities as it were, and the compound
acquires properties Avhich the elements did not possess
when free. Hydrogen is a gas ; Oxygen is also a gas.
When these two unite, heat and light are evolved, and
a compound is produced, consisting of the two gases,
but quite different from both in its properties. That
compound is Water, which is chemically an Oxide of
Hydrogen. It is not capable either of burning or of
INTRODUCTION,
supporting combustion, but can unite with other oxides
to lorm new and more complex compounds. Sodium is
a soft shining metal, Chlorine a suffocating gas. When
they combine the resulting compound is common salt.
AH the Elements have Names by which they are
distinguished, and the compounds formed by their
union have likewise names expressive of their com-
position. Sodium and Chlorine, when they combine,
form, as we have seen, common salt, the chemical
name for which is Sodium Chloride, that is a com-
pound of Sodium and Chlorine. Carbon (the most
familiar form of which is charcoal) combines with
Oxygen in two proportions, and the two resulting
compounds are called repectively Carbon Monoxide,
and Carbon Dioxide, to indicate that in the first there
is one atom of Oxygen, and in the second two ; this
latter substance was tirst known as fixed air, and is still
often called Carbonic Acid Gas, a name given to it
before our present system of chemical nomenclature
was made as perfect as it now is. A compound of
Oxygen and one other Element is called an Oxide, of
Chlorine and one other Element a Chloride, of Sulphur
and another Element a Sulphide, of Iodine and another
Element an Iodide, and so in other cases.
When the Oxide of a Non-metallic Element unites
with water it forms an acid^ that is a compound which
has a sour taste and reddens litmus. When the Oxide
of a metal combines with water on the other hand it
I forms an alkali, turning the red litmus blue.
When two such compounds, an alkali and acid, are
I brought together, their oxides unite, and a more com-
plex compound is formed, which is neither acid nor
[alkaline, but neutral ; it is usually soluble and crystal-
llizable, and is called A Salt. Many of the compounds
[contained in the soil, in manures, and in food, are salts,
lor are built up in the same way. Land Plaster is
[Oxide of Calcium (Lime) combined with Sulphuric
▼i.
INTRODUCTION.
I
Oxido, and is hence called Calcium Sulphate, hy tho
( /honnst ; the same Oxide united with Carbon Dioxide
forms Calcium Carbonate, common limestone or chalk.
If the Carbon Dioxide bo driven off Trom this latter by
heat tho Calcium Oxide remains as burnt liino ; when
water is now added it combines with the Oxide and
forms the Alkaline Hydrate. Calcium Oxide; united
with Phosphoric Oxide forms Cyalcium Pho8j)hate or
Phosphate of liime. Clay consists essentially uf Alum-
inium Oxide and Silicic Oxide, that is Aluminium
Silicate, which, altho' it corresponds to a salt in com-
position, is, like many other Silicates, not soluble in
water.
Tho V!)lements when in union with each other always
so exist in definite proportions by weight and volume.
They unite (with very few exceptions) iu equal
volumes compared in the gaseous state. But the
volume or atomic proportion, although always constant
in weight for the same element, is difterent in weight
for the ditferont elements. One volume or atomic
proportion of Hydrogen (which is the lightest element)
is reckoned as weighing 1, and a volume or atomic
proportion of Oxygen weighs 16, one of N. 14, one of
Sulphur 32 ; these are the atomic weights of the
elements respectively. Each element has a definite
atomic weight. i
As the atomic proportion or "atom" of an element has
a definite weight, so a compound also has its definite or
molecular weight. Two atoms or volumes of Hydrogen,
weighing 1 each, unite with one atom or volume of
Oxygon, weighing 16, to form one molecule of "Water
weighing 18. The molecular weight of a compound is
the sum of the atomic weights of its constituents.
In Chemical Notation every element is indicated by
a Symbol^ which consists, in most cases, of the initial
letter of the name of the element, as C for Carbon ;
where two or more elements have the same initial
INTRODUCTION.
vii.
Icttur, an udditiunal distiuctivu luttur is added when
necessary, as CI lor C'hlorine. The symbol stands for
one atomic proportion, that is one volume or " atom,"
of tlie element ; tliin is multiplied by placing a small
li<,'ure on the right hand side of the symbol, thus, CIj.
A Formula is simply formed by placing two or more
.symbols togetlier, to show the elements of which a
compound consists. Thus HgO is the formula for
Water, showing that this compound consists of two
volumes of Hydrogen and one volume of Oxygen ; as
the atomic weight, or weight of one volume, of Hydro-
gen is 1, the two atoms will weigh 2, and as the
atomic weight of Oxygen is 16, its one volume will
weigh 1 ; — the formula thus represents to us the exact
proportions by volume and weight of the elements of
which tlie compound consists. The use of a chemical
formula is to show the precise composition of a com-
pound body. .' ■ i,,, ^^'\i
A Chemical Eijaativn consists of two or more
fornmln-, or of at least one formula and two or more
symbols ; its object is to represent what is called a
" reaction," that is a change in the constitution, or
arrangement of the components, of a compound, or the
formation from free elements of a compound, or the
resolution of a compound more or less completely into
I its elemciuts. Thus, if we place a piece of the element
Sodium in contact with the compound Water, a chemi
seal change takes place : the sodium and water have
combined to form an alkali, but not the whole of the
water, for a gas, 11, is set free. The change is explain-
jed by the following "equation :" —
2 HgO + ^^82= 2 NaOH + H^
[Which we may read thus : two molecules of Hydrogen
lOxide (water) and two atoms of Sodium, yield two
{molecules of Sodium Hydrate and two atoms of
[Hydrogen. In every case where the algebraic sign of
?quality = is used in a chemical equation it is to be
viii.
INTRODUCTION.
\
read, not as "equal to," (which would suppress the
essential idea sought to be convoyed), hut as "ffielih" or
"yield" so and so. For examples of chemical formuleo
and equations, see foot notes on pages 35, 36, 37.
List of some Chemical Compounds mentioned in this
work, with their fowmhi;
Water.... '....HO
Silica (quartz, sand) Ki Oj,
Silicic Acid 2H30,Si 0, or H, Si 0,
Carbon Dioxide (Carbonic Acid Gas) C0„
Sulphuric Acid (Oil of Vitriol) H,, SO^
Phosphoric Oxide (Anhydride) PoO.
Phosphoric Acid .... 3Hj,0, P^O^, or ir.PO,
Calcium Oxide (burnt lime) CaO
Calcium Hydrate (slacked lime). .CaOjHjOorCaH-Og
Potassium Oxide K^O
Potassium Hydrate K^O, H^O or KHO
Sodium Oxide .Na^O
Ammonia NHg
Ferrie Oxide ^'^a^^a
Sodium Chloride (common salt) NaCl
Calcium Carbonate (marble, limestone)
CaO, COa or CaCO,
Potassium Nitrate (Saltpetre) . .K^O, NjjOj orKNO,
Calcium Sulphate (Plaster, anhydrous)
CaO, SO, or Ca SO,
Tri-Calcic Phosphate (bone earth)
3CaO, PjOg or Ca^PjOg
Bi-Calcic Phosphate (Reduced Phosphate)
2CaO HjO, PjOg or Ca^Hj,, 2 PO ,
Mono-Calcic Phosphate (Superphosphate)
CaO, 2 H^O, PjOj or Ca H„ 2 P 0,
Aluminium Silicate, hydrated, (Silicate of Alumina,
Clay) .AljO,, 2Si 0„ 2Hj,0
Aluminium and Potassium Silicate (Double Silicate of
Alumina and Potash). . . .KjO, AljO,, 6 SiO,
i
ppress the
"f/felils" or
al formuleo
S 37.
fd In this
H„0
. . . . Ki 0,
r H, Si 0,
.....CO,
. . Hj SO.
.... ^ 9^^ fL
or ir.po,
CaO
kCaH-O.
...K,0
or KHO
. . . . Na„0
NHa
. ...Fe,0,
NaCl
or CaCO-
J or KNO,
or Ca SO^
I- Ca,P,03
fa, 2 PO ,
^4, 2 P 0,
Alumina,
0„ 2H,0
Silicate of
>,, 6 SiO,
PREFACE TO THE FIRST EDITION.
In the preparation of this elementary work upon
the Principles of Agriculture, the autlior has been
desirous of avoiding, as far as possible, the use of
technical terms, in cases where other terms in general
use would convey the same idea. When it has been
necessary to employ such terms, they have been
explained in the simplest possible manner, so as to
render the book intelligible to all classes of readers.
Although the work is strictly elementary, the author
has considered it desirable to draw attention to certain
points in practice and in theory, which seem to be
insufficiently recognized by many of our practical and
scientific agriculturists.
London, January, 1878.
PREFACE TO THE SECOND EDITION.
The rapid sale of a large edition, and the favour-
able opinions which have been expressed of its utility,
encourage the hope that the " First Principles of
Agriculture" has not only been found useful for pupils;
under instruction in the elementary stage of Agricul-
tural Science, but of value to those who desire to
inform themselves on the subject. The alterations
which have been made in the Second Edition will
probably increase its utility.
London, December. 1879,
IN. . ..i
i . .'.■■. ', .- i
CONTENTS,
./
Chap.
■ * i
Paragraph
Pagr
I.
—The Soil,
. I— 28
• 7
II.-
—Composition of Crops, .
• . 29 35
. 17
III.-
— Fertilitv of the Soil, ,
• 36 47
. 21
IV.-
—Farm Manures, . . .
. 48— 58
• 27
V.-
—Artificial Manures, .
• . 59 93
. 32
VI.-
—Natural Manures, .
. . 94 124
• 51
VII.-
— Tillage Operations, . .
•125 143
. 64
VHI.-
—Rotation of Crops, . .
.144—157
. 71
JX.-
—Live Stock,
.158 176
• 77
X.-
—Food of Farm Stock, . .
,177—200
•85
't:ji';r
FIRST PRINCIPLES OF AGRICULTURE.
:aph
Pack
28
• 7
35
• 17
47
. 21
58
. 27
93
• 32
24
- 51
43 .
64
57 .
71
76 .
77
)0 .
85
CHAPTER I.
^ THE SOIL.
1. The cultivation of the soil is commonly
known as Agriculture, and the term usually includes
the several operations and the general system of man-
agement whereby the farmer is enabled to grow corn,
meat, wool, and various other marketable products.
The success of his work is determined by his producing
as large a supply as possible from the land, at the small-
est cost to himself, and with the least injury to the soil.
The object of the present work is to explain in familiar
language some of the circumstances which influence
these results. '
2. The surface of the land consists of earthy matter,
more or less finely broken, and this is called the soil.
This may be termed the raw material which the farmer
has to manufacture into products suitable for food and
clothing. He uses the soil for these purposes, calling
to his aid the agencies of animal and vegetable life,
and the stores of fertility which are present in the at-
mosphere. »
3. In some cases the soil is very shallow, and if you
dig a hole in the ground you will soon reach the hard
rock. In other instances there is a very considerable
depth of earth; and thus we have both shallow and
deep soils.
4. When a hole is dug into a deep soil — especially
if it be what is known as a clay soil — we observe a
marked change in the general appearance of the soil
%
AGRICULTURE,
[CH.
?Jf
some little distance below the surface: sometimes it is a
difference of colour, sometimes a variation in the rough-
licss, but whatever the difference may be, it is clear to
the eye that there is a difference in the character of the
soil. The portion that so differs from the surface soil is
called the sub-soil, or under-soil. In speaking of the
upper or surface soil we usually call it the soil, and that
portion which lies below it is known as the sub-soil.
5. The question naturally arises, how is it that
the land is thus covered by this earthy matter, and
whence did the soil come ? Soils are produced
by the breaking up or crumbling of rocks. If a rock
were reduced into powder either by grinding, or by any
other mechanical means, that pulverized rock would be
a soil. But soils are not formed liy rocks being pul-
verized by man's industry ; natural agencies carry out
this work very perfectly, sometimes with, and at other
times without, our co-operation.
6. There are three agencies which thus turn rocks
into soil, and thereby produce for the farmer the earth
from which he makes his crops to grow. Water is one
of these agents. If water falls upon or soaks into a
piece of rock, it has a tendency to dissolve some por-
tion of the stone, and then pass away with its spoil as
soon as other water is ready to take its place. Thus,
rocks are softened by water and some portions dis-
solved out of them.
7. Water also acts powerfully because it contains
some atmospheric air in it. Rain-water in falling
through the air takes into, and amonC'St its particles,
some portion of the air through which it passes, and
retains it. Thus water has generally some atmos-
pheric air in it. This air is a mixture of two gases —
oxygen and nitrogen — with some others in small pro-
portions, but of the latter we now only notice one,
carbonic acid.
8. When water carries into a rock the oxygen which
it contains, this gas has ^ tendency to fyrm chcrnicaj
:i.]
W comL
H Whei
8 In th
S have
9 actio
S out c
wk- ^^^ ^^
' and 1
actec
'Wk a r\ H
^
^.]
FORMATION OF SOILS,
combinations with some of the materials in the rock.
When carbonic acid is also present it helps to dissolve
In the water, portions of the rock which would not
have been soluble in pure water. Thus the solvent
action of water and its associated gases dissolves
out certain portions of the rock, and thereby the rock
has holes made in it, which gradually increase in size,
and thus expose a larger surface to be subsequently
acted upon by further supplies of water.
9. There is a third agency which exerts its influence,
and often does so with great force, that is, frost.
When the surface of a rock has been penetrated by
water, and the temperature of the air falls below the
freezing point, the water becomes frozen. As water
freezes it gets bigger, and the particles of a wet rock
are pushed apart so as to make room for the water
which is freezing. When the frost has ceased and a
thaw takes place, portions of the surface, being thereby
released from the solid bands of ice, are thrown off
from the rock. The extent to which this takes place
depends in a great measure upon the size of the holes
which the water and gases may have made in the
rock. Sometimes the openings scarcely penetrate
below the surface, and in such cases the surface of
the rock only is affected; at other times large masses
of rock are thrown off.
10. These three agents wear away our hardest
rocks, and thus they are broken down and pulverized
into soil. Softer rocks are of course acted upon more
rapidly than hard rocks, but every rocky surface is
thus made to yield its contribution to the soil. The
lower forms of vegetation then establish themselves
on this newly-made soil, and their rootlets penetrate
and obtain their food from it. In due course these
plants die, and add decaying matter to the soil, which
thereby becomes fitted for the support of higher forms
of vegetation, and these prepare the way for those of
Still higher organisation.
10
AGRICULTURE.
II. If soils so formed were allowed to remain
where they were first produced, we should find very
little differer^:e between those soils and the rocks
from which they were formed, except so far as regards
their being in a more broken condition. But the
study of geology shows that great changes have taken
place on the surface of the globe, and that when soils
have thus been formed from rocks, they have fre-
quently been washed away and mixed with soils
produced from other rocks. Soils of this character
are often found in our valleys, and are distinguished
as alluvial soils. In many cases these mixed soils
have been again formed into rocks, and after long
periods of time, these rocks have again become con-
verted into soil. Animal and vegetable life have also
exerted very great influences upon the character of
many of these reconstructed rocks. Thus our soils dif-
fer very much in character and composition, according
to the varying character of the rocks from which they
may have been produced, and also according as they
may have been more or less intermixed with other soils.
I a. There are some soils which are not produced by
these means, such as Peaty Soils. These consist
of vegetable matter which has grown and decayed,
generally in the place where these soils are found.
Their mode of production is peculiar. They are
generally found in places from which the water cannot
easily pass away. Here aquatic vegetation and mosses
establish themselves, and as they require a liberal
supply of water for their growth, they flourish luxuri-
antly. Growth after growth takes place, decaying
matter accun)ulates, which encourages further growth,
su that ultimately the rising bed of peat is held only
in check by the supply of water. When they have
grt)\vn up as higli as the water allows them to grow,
touglier and more woody plants establish themselves;
these givi? tlic harder and firmer surface which is
fouiul upon our peat bogs and mosses,
ANAL ySIS OF SOILS.
Tl
to remain
i find very
the rocks
as regards
But the
lave taken
when soils
have fre-
with soils
character
tingiiished
lixed soils
after long
:ome con-
have also
iracter of
r soils dif-
accordirig
diich they
ig as they
•ther soils.
)duced by
se consist
decayed,
re found.
They are
:er cannot
id mosses
a liberal
;h luxuri-
decaying
;r growth,
leld only
liey have
to grow,
Mil selves;
which is
13. These peaty soils therefore differ essentially
from the soils which have been produced by the
mlverization or powdering of rocks. Peat soils con-
sist almost entirely of vegetable matter, which often
reaches as much as 97 percent., and they contain very
little mineral matter; whilst soils produced from rocks
ire chiefly composed of mineral matter, and have only
ft small proportion of vegetable matter.
14. For the convenience of being able to describe
rith accuracy the character of soils, so that soils of the
same character may be called by the same names, it
las become necessary to classify soils according to
their texture and condition, as well as by their corn-
)osition. The character is indicated by a mechanical
malysis, and the composition is determined by chemi-
cal analysis. By these means we can inform ourselves
|with great accuracy as to the composition and charac-
|ter of any soil, and establish a regular classification.
15. The mechanical analysis of soils is largely
fbased upon the proportions of clay and sand which they
jcontain. The term Clay is applied to the finer portions
lof the mineral matter of the soils. These portions have
)y various means become so reduced in size that they
ire perfectly soft to the touch, and when pressed in the
land retain the form into which they may be moulded
)r pressed. The clay which is used for makirg bricks
ind pottery is familiar to every one. It is soft and
iasily moulded in the hand, and when water is placed
fn any hollow on its surface the water does not readily
ioak away,
16. Sand is just the reverse. It really consists of
rexy minute stones, and when pressed in the hand it is
jritty and hard to the touch. If any attempt be made
to mould it into any particular shape, it does not keep
the form so given to it. If a hollow be made on the
surface and water be poured into it, the water quickly
)asses til rough it. In the sand upon the sea-shore we
i^ve a familiar example of the sand in soils,
X9
AGRICULTURE,
rcj
17. These two portions of the soil are strikinglj
distinct, and they are therefore used as the foundatioj
of a system upon which we can base a general classi^
fication of soils. The manner in which the quantity
of clay and sand in a soil is determined is exceedingly
simple. When a sample of soil is to be so examined]
measures are taken to separate the stones and portions)
of rock which are present. These are not a part of the,
true soil; they are simi)ly rock or stone mixed with the^
soil. The soil upon which the farmer has to rely fori
his crops is the fine earthy matter, and not the stonesf
which are mixed wiih it. It would, however, be a|
serious error to consider these stones and pieces of rockl
as useless to the farmer. These have their duties toF
perform, as we shall hereafter see; but, for the presentl
purpose, they must be distinguished from the soil!
which has to be examined.
18. To obtain the fine earthy matter from a soil^ al
small sieve or piece of wire work should be used, and!
thvi coarser portions thereby separated and carefully
dried. Two hundred grains of the sifted soil may]
then be thoroughly mixed with about half a pint ofj
water, and well shaken for some few minutes. As
soon as this has been accomplished, the.vessel maybe
allowed to remain quiet for a short time, during which
the sand falls to the bottom. Whilst tlie fine particles'
of clay are still floating in the water, it should be
quickly poured into another vessel, leaving the sandj
behind in the first. If the clay be not entirely re-
moved in the first attempt, the sand may be again;
washed, and any clay poured into the vessel containing
that first removed. You have thus made a separation
of the soil, which will enable you to determine its
character, and to classify it accordingly. More ad-
vanced and accurate processes are sometimes adopted
(see Professor Church's " Laboratory Guide"), but
this simple process gives results which are sufficiently
g^tisfactory for all ordinary purposes.
CLASSmCATlON OP SOUS.
a
19. The sand and clay are afterwards carefully dried
id weighed. If you found the weight of sand equal
the weight of clay, this would represent, in other
^ords, 50 per cent, of sand. A soil of this composition
known as a Loam, as shown in the following
ible: —
Name of Soil.
Sand,
Clay,
Loam,
PERCENtAGE OP SaND.
1
So to 100
40 to 60
— to 20
Ills necessary, however, to arrarge for other pro-
portions of clay and sand, and these are distinguished
fs Sandy loams and Clay loams. They take
itermediate position between the loam and the two
jrimary soils, sand and clay, and the table of classi-
Ication thus becomes more extended —
Name of Soil.
Percentage of Sand.
Sand,
Loam,
Clay,
Sandy Loam,
• • •
Clay Loam,
80 to 100
60 to 80
40 to 60
20 to 40
— to 20
20. If, in the experiment indicated above, the soil
lad contained more sand — say from 60 to 80 per
lent, of sand — it would then have been classified as a
mdy loam. If there had been less sand and more
pay — say from 20 to 40 per cent, of sand— then the
)il would then have been classified as a clay loam.
'hese groups of soils are based upon the percentage
If sand, and the residue in each case represents the
proportion of clay. It will be observed that soils
re grouped together, having a moderate variatioa
H
AGRICULTURE,
tctf.
<":
n
\\
IS
\\
'1
H
in composition. There is in fact a range of 20 per
cent, for each of these groups. If, for example, a
soil contains 10 per cent, of sand and .the rest is
clay, we should call it a clay soil. If, again, ?
soil contained 40 per cent, of sand and the remainder
is clay, it would be a loam. This is a classification
which will be sufficient for our purposes, and may
conveniently replace the complicated systems which
are supposed to be necessary when treating the sub-
ject more in detail.
21. In addition to this physical analysis of the soil
we have to consider the several ingredients of which
it is composed, and these are determined by chemi-
cal analysis. Chemistry reveals to us the fact that
soils contain a large number of different substances,and
that the proportion in which they exist is very variable*
It is desirable that these substances should be familiar
to the mind, and their general influences clearly
understood. They are briefly referred to here without
going into those fuller details which may be found in
any textbook on chemistry.'
22. The soil consists of two distinct classes of
bodies, viz., those which are mineral or inorg^anic
matters, and those which are organic substances.
When a soil is exposed to the action of fire these two
groups are separated, the organic matter is burnt off
and dispersed, in a gaseous form, but the inorganic
matter remains.
23. The Inorganic matter found in soils may
be briefly noticed here. Silica or silicic acid first
claims our attention. This body forms a very large
proportion of sandstone, and it exists abundantly in
granite and other crystalline rocks. When combined
with alkalies or with an alkaline earth, it forms
silicates, a series of bodies of the utmost importance in
1 Johnson's *' Catechism of Agricultural Chemistry," by Voelcker, foU
lowed by Roscoe's '• Lessons in Chemistry," nay be named as presentr
U>g valuable elementary instructioo.
1.]
TNOKdAmC MA rVRk OF SOJtS.
ts
reference to the fertility of the land. Clay is chiefly
composed of silicate of aluminai that is to say,
silica combined with i^lumina. The fertility of clay,
however, is very largely dependent upon the presence
of a peculiar form of silicate of alumina, which de-
mands special notice.
24. Some few years since Professor Way carried out
an investigation into the character of the silicates of
alumina, and disclosed truths of immense importance
which have not been generally understood, and conse-
quently have not been taken advantage of. He
showed the existence of a class of bodies which are
te4:med double silicates. These were silicates of
alumina in which part of the alumina had been replaced
by an equivalent quantity of some other substance,
such as lime, soda, potash or ammonia. Thus we
have these double silicates in soils as silicate of
alumina and lime, as silicate of alumina and soda, as
silicate of alumina and potash, or as silicate of alumina
and ammonia. These substances will hereafter be seen
to be exceedingly important, and a familiar acquaint-
ance with them is most desirable.
The Alumina also possesses in one respect an
exceptional character. Whilst it is most valuable in
assisting other bodies to enter into the crops growing
upon the land, it appears to act rather as an " out-of-
door servant," carefully avoiding going into the plant.
25. Phosphoric acid is by general consent con-
sidered as one of the most important substances found
in the soil. Its influence upon the fertility of the land
is very great, for every cultivated plant requires a
supply for its successful growth. In combination with
lime it forms a large portion of the skeletons of animals,
and the demand which cultivated plants thus make
upon the soil for phosphoric acid enables them more
perfectly to supply the requirements of the animals by
which these are afterwards used in food. A supply of
phosphoric acid in the soil is therefore of very great
-i
t6
AGklCULTUHn,
tctf*
ll
• s\
importance. It is never found in the soil in largfl
proportion: in our richest soils it barely reaches*5 per
cent., that is, :n loo lbs of soil there is rarely as much
as ^ lb. of phosphoric acid.
26. We here giv^alistot the more important bodies
usually found in cultivated soils, so that the student
may have the opportunity of making himself ac-
(juaintod with their properties from his textbook oH
chemistry:
Inorganic Matters in Soils.
Silica.
Phosphoric acid.
Carbonic acid.
Sulphuiic ac'd.
Chlorine.
Alumina.
Lime.
Ammonia*
Potash.
Soda.
Magnesia.
Oxiao of iron.
fi
27. In addition to the inorganic matters of soils we
have a second group of substances existing in them as
organic matter. This matter consists of substances
which may have grown under the influence either of
vegetable or of animal life, and have consequently
been organized as part of some living plant or animal.
The process of decay in the soil brings these
vegetable or animal remains into such a condition that
they again become available for' yielding nourishment
to vegetation. Any inorganic matter which had
formed part of the structure of the vegetable or ani-
mal, becomes an addition to the mineral matter of the
soil, whilst the organic matter forms a series of sub"
stances which practically yield to the soil —
Carbon, with the elements of water (Oxygen and
Hydrogen), in various forms of combination;
also
Ammonia and other nitrogenous matters.
28. The inorganic and organic substances in the
soil constitute a very large number of bodies, but by
the aid of chemical analysis the composition of soU^
I]
ASHES OF PLAINTS.
17
can be accurately determined. The knowledge we
thus obtain enables us to supplement the results
obtained by the mechanical analysis (19), and thus
we can extend the classification of soils. The me-
chanical analysis enables us to determine whether
a soil is a sand, sandy loam, loam, clay loam, or clay
soil; and the chemical analysis enables us to determine
whether they are calcareous or peaty. If there should
be any large quantity of stone, gravel, or rock, or
other exceptional matter mixed with the soil, these
would add an additional character; as for exami)le,
a calcareous loam with little or much stone, gravel,
or rock; or a sand with a large quantity of iron;
pr a loam with much organic matter, etc., etc. The
term marl has been proposed for soils which contain
from 5 to 20 per cent, of lime, but this is a term which
should only be used for describing those beds of
earth commonly known as marls.
CHAPTER II.
COMPOSITION OF CULTIVATED CROPS.
29. Ey the aid of chemistry we are enabled to
learn what is the composition of our cultivated crops,
and the sources from which plants obtain the materials
of which they are made. We find that every plant
has two distinct groups of bodies within its structure,
and that these may be distinguished as Organic and
inorganic matter.
30. If any vegetable matter be carefully burnt, by
far the greater portion disappears in the form of
smoke, but a portion remains behind in the form of
ash. This ash consists of mineral matter, and it is
known as the inorganic matter of plants. It is
sometimes described as "the ashes of plants," but in
each case the mineral matter of the plant is referred to.
When this ash is analysed it is found to consist of a
large number of different substances, which are present
11
tl
AGRICULTURE,
[CH.
,ii|
III
i^
in (Jiff erent kinds of plants in very different proportions.
One variety of plant is found to contain more of « n;
material than ancnlier kind of plant, and the U tai
quantity of ash also varies. Taking the entire raUj^c
of cultivated crops, we find that, with one exception
(24) all the inorganic substances named as present
in the soil (26) are taken up by plants and built into
their structures. It is also known that plants take up
this inorganic or mineral matter with some regularity,
selecting only that which they retpiire, and refusing to
use that which is not desirable for their growth.
31. That portion of the plant which is burnt off is
known as the organic matter. In the plant it exists
in a great variety of forms, but these have been grouped
into two classes — those which contain nitrogen are
called nitrogenous bodies, whilst those which do
not contain nitrogen are called non-nitrogenoUS
bodies. This is a distinction wliich must be carefully
remembered, for those organic substances are not only
distinguished by this difference in their composition,
but the presence or absence of nitrogen also deter-
mines the work they can perform.
32. The following is alistof the principal substances
which constitute
The Organic Matter of Plants.
Non-nitrogenous Bodies.
Starch.
Gum.
Sugar.
Cellulose and woody fibre.
Oil.
Nitrogenous Bodies.
Albumen.
Fibrin (gluten).
Caseni (Icgumin).
!1
The non-nitrogenous bodies are all composed of
the three elements — carbon, hydrogen, and oxygen.
Because they contain carbon, they are often called
carbonaceous, but it is more convenient to describe
them as non-nitrogenous. The bodies named in the
nitrogenous group contain carbon, hydrogen, and
oxygen, but they also contain nitrogen, and hence
11.]
ORGANIC MA TTRR OF PLANTS,
19
the name which distinguishes them. It may be well
at this stag*; to notice very briefly the several bodies
we have thus divided into two classes.
33. Starch is a white granular body, very abundant
in vegetation, especially in corn and root crops. If
you place a little wheat flour in a fine gauze bag,
and wash it in a glass, the water quickly assumes a
milky api)earance. In a short time a white deposit is
formed in the glass, and the water has again become
bright and clear. The sediment thus obtained is
starch, which has been separated from the wheat
flour. If the bag were now opened, a glutinous mass
would be found, in appearance something like soft
threads of india rubber. This is the gluten of wheat,
to which we shall have to refer subsequently. Gum
exists in plants generally in a liquid condition, but we
occasionally find it thrown out on the surface in a
more or less hardened and transparent form, especially
in the case of fruit trees, when the bark has been
injured. Sugar is also found in vegetation in a
liquid form. In the well-known sugar-cane, sugar-
beet, and sugar- maple, it is found in great abundance,
and from all of these sugar is obtained for the public
supply. You should, however, remember that it is
present in our cultivated plants, even when not in
sufficient quantity for it to be separated for use. It
has many important duties devolving upon it in pro-
moting the growth of the plant, and its passage through
the plant, mingled with the sap, enables it to perform
these duties. Cellulose is so called because it is the
matter of which the cells of plants are constructed,
and it is sometimes known as cellular matter. It
varies very much in its firmness and strength. When
first it is produced in the plant, it is excessively tender
and fragile, but as it becomes strengthened by growth
so it gradually becomes more rigid and tough, and at
length assumes the form of woody fibre. These
bodies are very similar in composition, and are capable
I- !
M
1
90
AGRICULTURE,
[CH.
under certam circumstances of passing from one form
to another. It is worthy of note that although the
quantity of carbon varies slightly, the weight of oxygen
in each is exactly eight times the weight of the
hydrogen. Oil is found in large quantities in the
seiids of some of our cultivated plants — such as
linseed, hemp, and cotton seed; in smaller quantities
it is found in the grain of wheat, barley, oats, and
other varieties of corn.
34. The three nitrogenous bodies are exceedingly
similar to one another in composition. It has been
already stated, that they not only contain carbon,
hydrogen, and oxygen, as did the several bodies of
the other group; but they also contain nitrog^en,
and because they contain nitrogen, thev are called
nitrogenous. They are also called alouminoids,
after the name of their leading representative, albu-
men. This substance occurs nearly pure in the
white of the egg. It exists also in the juices of plants,
especially in corn and " roots." The gluten which
is separated from the flour of wheat in the manner
described (33), is largely composed of fibrin an
albuminoid which occurs in blood, from which it is
readily separated by gently beating the fresh blood
with a few twigs. Little threads or fibres will soon
attach themselves to the sticks, and these will consist
of the fibrin of the blood. We shall hereafter see that
fibrin, or gluten, is an ingredient which largely deter-
mines the value of food. Casein occurs mixed with
fats in the curd of milk; it is also found in peas,
beans, &c., in which case it is sometimes called
legumin.
35. We may now proceed to notice briefly the
sources from which plants obtain those substances
which we find them to contain. It is not difficult to
see that the inorganic matter is obtained from the soil,
because there is no other source from which these
materials can be obtained. It is also well known that
n.]
SOURCES OF PLANT FOOD.
91
solid matter cannot enter into a plant so
long as it retains its solid form; but it may be
received when it has become a liquid, by being
dissolved in water, or when it has taken the form
of gas. It may therefore be taken as a rule, that
the inorganic matter in plants is obtained only
from those portions of the soil which are
soluble, or capable of becoming soluble. There are,
however, two bodies — carbonic acid and am-
monia—which are of necessity associated not only
with the inorganic bodies, but are also present with
the organic group. They are, moreover, to a certain
extent exceptional, for plants not only receive these —
and water — with the soluble matters obtained from
the soil, but they also receive them iroiA the Stores
existing in the atmosphere.
CHAPTER III.
FERTILITY OF THE SOIL.
36. In addition to the physical and chemical classi-
fication of soils, we have another point of character
which is distinctly recognized and determined by the
cultivation of the land, viz., the fertility or barrenness
of the soil. We can explain by physical and chemical
investigations, the causes which influence the produc-
tive powers of land, and in many cases these researches
indicate the ttieans whereby those powers may be
increased or maintained. In the first place, a clear
distinction must be drawn between those portions of
the soil which are capable of yieldin, nour-
ishment to vegetation, and those which cannot do
so. A soil may contain large supplies of
every ingredient which a crop requires, and may
still be unable to yield tnem to the plant.
The grea,t truth must be fully realized, that it is
123
AGRICULTURE,
[cH,
oftly that portion of the soil which is capable
of oeinz dissolved by rain-water which is
aVdlidble as food. It is of no practical advantage
to a growing plant, that the soil should contain food
which will not be ready fo use until the next year, or
the next century. The lifv and growth of the plant is
determined by the supplies which are then ready
for use, or coming into use.
'},']. It has therefore been necessary to distinguish
the inorganic matter according to its soluble condition.
Those portions of the soil which are ready
for use, or in other words, can be dissolved in rain-
water, are known as the active ingredients of the
soil; whilst those which are not ready for
use, because they are not soluble in rain-water,
are termed dormant or sleeping. The distinction
between the two conditions is exceedingly simple;
but the influence resulting therefrom is of the greatest
importance. An analysis of a soil which represents
the total composition of a soil, is of little or no prac-
tical value, unless it distinguishes between
that which can be used by the crop, and
that which cannot. The farmer wants to know
what ingredients the land contains, which will be of
service for the crop he is going to sow, and if an
analysis leads him to rely upon all the substances in
the soil being ready for his use, he will be deceived.
Porall practical purposes, a chemical analysis must, in
the first place, separate the dormant matter of the
!Soil from that which is active, and must thus inform
the farmer what there is in the soil which he can
make use of. Without this distinction being drawn,
the chemical analysis of soils may be of scientific
interest; but it will be calculated to mislead those
who fail to distinguish between that which can be
used, and that which cannot be used, or, in other
mrords, between the active and dormant con-
stituents of the soil.
m.] ACTIVE AND DORMAl^T MATTER, 23
2t^. Whilst the active ingredients of the soil are
useful for the immediate requirements of vegetation,
the dormant ingredients have also their duties
to fulfil. These constitute the reserve fund of
the soil, and secure its future fertility. A bad
farmer may rob the land of very much of its active
matter, and by frequent removal of crops from the
land take away its immediate fertility, but he cannot
take away that which is in a dormant condition. It
is only the good farmer who gets help from this store;
and we shall hereafter point out why the one is re-
warded by good crops, whilst the other is punished
for his bad management. For the present it is enough
to remember that the dormant matter of soils is a
reserve of fertility for future years.
39. It will be important to know how this dor-
mant matter becomes useful for vegetation. It
is changed into the active condition in the
following manner. You have seen that the rain-water
containing as it does carbonic acid and oxygen, and
also the frost, break down even the hardest rocks, and
by their continued action they at length dissolve up
much of the finely broken portions of these rocks.
Exactly the same result is accomplished in the soil by
exposing it to the air, rain, and frost, and by allowing
the rain to pass into and through the soil; thus when
the soil of a field is ploughed up roughly before
winter, and exposed to the air, rain, and frost, it
is not only broken up into fine condition, but the sur-
face of the little fragments of the soil is so acted upon
that some portions become soluble in water,and
ready for being taken into the circulation of a growing
plant. These are the natural agencies by which some
of the dormant matter is made ready for vegetation by
becoming active; there are other means for assisting
the same change, but these will be more conveniently
noticed hereafter.
40. We have already noticed the fact that plants
s[
84
AGRICULTURE,
. f '. • . \
tcH.
draw their inorganic matter and also some of their
organic matter from the soil. If this demand on the
soil is continued without some return being made to
the soil, it is clear that the land will become
exhausted, and will not be able to supply the re-
quirements of the crops. It will, therefore, not only-
become exhausted, but as a consequence will be-
come less productive. The soil being the only
source from which a crop can obtain its inorganic
matter, exhaustion arising from any deficiency of this
portion of the plants' food is quickly observable. It
is desirable that you should realize what crops remove
from the land, and this is shown m the following
table.
41. Inorg^anic Matter removed from an acre of
land, by average crops of the following kinds: [Play-
fair)
■
Wheat.
Beans.
Turnips.
Clover
25
Socxslbs
25
28oolbs
Bush.
of
Bush.
of
20 Tons
6Tons
2 Tons
Corn.
Straw.
Corn.
Straw.
Bulbs.
Tops.
Hay
lbs.
lbs.
lbs.
lbs.
lbs.
lbs.
lbs
Potash,
7"49
i8-2i
22-63
89-17
"5"73
75'95
.53
Soda
'97
•90
6-68
2-69
22-98
16-23
7
MuKiicsia, . .
3 '07
4-11
5*03
1 1 '24
12-27
c-27
35
Lime, . . . ,
•8s
9"34
3"03
33*58
.37"87
69-81
III
Phosphoric Acid,
II*47
8-15
23-67
12-16
31-11
27-87
20
Sdlphurlc Acid, .
•08
5-82
•61
1-83
42-26
36-56
13
Sllii'ft. . . , .
•84
101*82
•72
11-84
11-66
2-s8
10
Peroxide of Iron,
"20
1-32
■35
—
3'7i
2-58
3
('ot«n\on Salt,
■03
*33
•90
7' 1 5
28-69
38-15
8
Curbonlc Acid, .
25
21-71
21.
—
150
63
168
340
300
259
42. These numbers may be taken as fairly repre-
senting the inorganic matters generally re-
moved b)^ these crops, but they will vary according
to the weight of the crop, and the character of
the soil. These figures must therefore be looked
upon as giving only a general idea of the materials
m.]
DEMAI^DS UPON THE SOIL.
25
removed from the land. It would be difficult to re-
member all these figures, but they represent certain
general facts which should be remembered.
43. We see that different parts of the same
plant contain very different quantities and
varities of inorganic matter: for instance, the silica
in the corn of wheat is about i lb. for each acre grown,
whilst in the straw there is 100 lbs. and when you
examine the straw of wheat you see the bright glassy
coating which requires this silica. You also see that
beans only require about 12 lbs. of silica per acre,
whilst wheat requires 102 lbs., and one lesson this
teaches is that different crops require different
kinds of food. If you notice the requirements of
the turnip crop, you will see that an acre of turnips
requires about 200 lbs. of potash, and nearly 40 lbs.
of soda, whilst a crop of wheat only requires about
26 lbs. of potash, and scarcely 2 lbs. of soda. You
must not lose sight of the fact that as different
crops require different kinds of food, they therefore
draw from the land different kinds of in-
organic matter. By the removal of our various
crops from the land, we remove in them large quan-
tities of those inorganic matters which are necessary
for keeping the land fertile, and one of the great
objects to be accomplished in successful farming is to
be able to do this, and at the same time make the
land more productive every year. It is, however,
quite possible for soils to be rendered unpro-
ductive by the plant-food they contain being removed,
and the land thereby becoming exhausted.
44. Some soils are unable to grow crops by reason
of their having some injurious matter present, such as
some of the lower compounds of iron, salt, and acrid
organic matter, all of which prevent healthy vegetable
growth.
45. Other soils are unproductive because their
mechanical condition is unfavourable for vege*
n
dS
AGRICULTVRE.
[CH.
table growth. The roots of plants may be unable to
penetrate a soil because of its haidness, or the
presence of stagnant water may have the same effect.
A plant in sending its roots into the soil, requires
not only that the roots shall be able to extend
through the soil in search of food, but that the soil
shall also be in a healthy condition. A supply of water
is necessary fortheroots, but a supply of air is equally
necessary. When the soil is charged with an accumu-
lation of stagnant water, the roots which come within
its influence are unable to discharge their func-
tions in ahealthy manner, and thegrowth of vegetation
is consequently very slow and imperfect.
46. Another condition of fertility is the presence in
the soil of all the food which the crop requires. An
abundance in the supply of one portion of the food
does not compensate for a short supply of another
equally important portion of the food. Hence the
fertility of a soil is determined by the quanity of that
essential food which is present in the least propor-
tion, and not by that which is in great abundance.
To illustrate this by a familiar example, a builder may
have plenty of stone for the construction he intends to
erect, but if he has little mortar his progress is soon
stopped for want of a further supply. It would not
assist him if you increased his supply of stone; he wants
something else, and until this is ready for his use he
can make no progress. It is the short supply of
mortar which regulates his work, and not the abun-
dance of stone. It is just the same with vegetable
growth; the i)lant requires a variety of materials, and
that essentinl material which is present in the least
abundance regulates the crop, and not those which are
more ]>lentifully supplied.
47. The terms good and poor land have reference
to the relative productive powers of land. In a good
soil we have a combination of conditions favourable
for the production of large crops — we have a soil wiii*
111.]
CAUSES OF FERTILITY.
m
a complete supply of food, and it exists in a condition
favourable for vegetable growth, and we also have it
r.ituated in a climate suitable for the crop to be grown.
Such a soil properly cultivated constitutes a good and
fertile soil. If either of these conditions is wanting,
then it ceases to be good and productive land. You
will observe that no one condition is sufficient to make
the land productive; the plant-food must be there, and
under such circumstances that the plant can use it,
the climate must also be favourable for the crops, and
the soil must be well cultivated; but the absence of
any one of these conditions renders the land unpro-
ductive and poor for that particular crop.
CHAPTER IV.
FARM MANURES.
48. The more frequent growth of various crops
having been found advantageous, the use of manure
is now recognized as absolutely necessary for pre-
serving the land in a productive condition. It may
be well to see what manures are, and how they accom-
plish this work. Much of the vegetable produce
grown upon the land has to be kept upon the farm,
and reduced into such a condition that it can be
again added to the soil as manure. If we take a
crop of wheat as an example, the corn is separated
trom the strav/, and the corn having been sent to
market, the straw is used for stock, and finds its way
to the manure heap after it has been so used.
Other crops, such as those known as root crops —
mangels, turnips, swedes — are consumed by stock on
the farm; and the green crops, such as clover, vetches,
rape, mustard, &c., are similarly used. These crops
are therefore used for a twofold object — first, to
nroduce meat, wool, milk, «;heese and similar market-
2d
AGRICULTURE.
[CH.
I
able products; and, secondly, to produce manures
for the land.
49. There are two ways in which this vegetable
matter is added to the land as manure. When sheep
and other stock are fed with it upon the land, the
excrement of these animals conveys to the soil those
portions of their food which have not been added
to their bodies, or used in the support of their warmth.
The excrement returns to trie soil very valuable
inorganic and organic matter which the plant
had originally drawn from the soil, and so far
as these matters are restored to the land, so far its
exhaustion is checked. In the table already given
(41) you have seen how largely crops of turnips —
which are usually fed on the land — draw upon the
soil in their growth; if therefore you return this matter
to the soil, from a chemical point of view, you
render it almost as capable of producing another
growth as it had previously been.
50. In the form of farm-yard manure another
large portion of this vegetable matter finds its way
back to the land. The course of operation is not
as simple in this case, for whilst in the former instance
the manure became quickly intermingled with the
soil, in this case it has to be preserved until it can be
carted to the land. In the necessary treatment which
this manure has to undergo there is a great liability
to loss.
51. The production and management of farm-yard
manure are based upon certain principles which are
easily understood, and with these you will readily be-
come familiar. This manure consists of the straw, or
other litter or bedding for the stock, and of the excre-
ments the stock may produce. It is well known that
the excrement of the different kinds of stock kept
upon a farm varies very considerably. That from
horses ferments rapidly and gets very hot, that from
cattle is slow to ferment and is consequently a cool
[CH.
ures
table
iheep
i, the
those
idded
rmth.
luable
plant
so far
far its
given
nips —
Dn the
matter
IV, you
mother
mother
its way
is not
istance
ith the
can be
t which
ability
m-yard
ich are
iilv be-
raw, or
excre-
iwn that
k kept
lat from
at from
a cool
IV.]
FARM- YARD MANURE.
^
manure, whereas the manure obtained from pigs is
intermediate. One of the first things to be secured is
an even distribution of the different kinds of
manure, so that the bulk of manure may have a
similarity of character. This is most necessary,
if any measures are to be adopted for regulating the
fermentation; otherwise one portion is too hot,
and another portion is not hot enough, and that
treatment which is favourable for one part is injurious
for another. An even distribution is therefore
the first essential; this being secured, the fer-
mentation of the heap can be readily controlled.
52. For our present purposes, this fermentation may
be familiarly described as a decay or rotting, brought
on by the decomposing influence of the nitrogenous
matter present, whereby the non-nitrogenous matters
present also undergo decomposition. The chief pro-
ducts of this decomposition are ammonia, and
either carbonic acid, or some one or more of the
organic acids, such as the ulmic acid or humic
acid. The ammonia is formed from the nitrogenous
matters in the manure, and the non -nitrogenous
matters may yield either carbonic acid or the organic
acids we have named above, according to the manner
in which the decomposition of the manure takes place.
If the manure be allowed to get dry and hot, then
carbonic acid is formed; but if the manuie be kei)t
moist, one of the organic acids is produced. If car-
bonic acid be formed, it combines with ammonia,
and we have carbonate of ammonia formed.
This is a very volatile and pungent smelling salt, of
which you will have very little doubt after you h:ive
once experienced its influence. But if instead of
carbonic acid being formed, we get one or more of
the organic acids produced, then you have, say,
ulmate of ammonia or humate of ammonia
formed, which has a very different character. You
have probably seen the black streams which
30
AGRICULTURE,
[CH.
run from manure heaps. These usually contain
humate and ulmate of ammonia. This drainage is
black and often offensive; but it is not in any way
pungent, and the reason of this is, that the am-
monia is not present as carbonate of am-
monia.
53. The successful fermentation of the manure heap
is very largely dependent upon the temperature at
which it is allowed to proceed. The chief con-
dition of success is to avoid loss. If the ammonia
formed in the heap be allowed to take the form of a
carbonate of ammonia, and pass away into
the air, the work is a failure by reason of the most
valuable portion having been lost. If on the
other hand the fermentation be so controlled that
the ammonia is preserved, then we may fairly
consider the management a success.
54. The temperature maj' be easily regulated by a
1'udicious use of water. The manure should be
cept moist without being drenched, and the soakage
from the manure should be used for this purpose.
You may naturally enquire how you are to know when
the manure requires more water.? If on moving any
portion you find any pungent smell of ammonia, be
satisfied that it requires to be moistened; or if you
find the manure dry, or having a mildewed appearance,
you may know that -it should have been moistened
long before then. A want of care in this respect
involves great losses every year, for the ammonia
lost is our most expensive manure. Many farmers
waste it by sending it into the air, and then go to
market and buy some more at ;^ioo per ton.
55. You must also understand that there is another
way in which this ammonia is lost, and that is, by
allowing too much water to fall upon it, and wash
out the black matter already referred to, and this too
often runs into the roads and ditches, and is lost.
Farm-yard manure is thus seriously injured, from
IV.]
FERMENTA TION OF MANURE,
want of proper care, until its valuable constituents are
either sent into the air or washed into the ditch, and
the humorous description of the late C. VV. Hoskyns
becomes verified in "Drychaff 's dung-cart — that creak-
ing hearse — that is carrying to the fields the dead
body whose spirit has departed." Very imperfect
ideas are entertained of the enormous losses which
are thus suffered by men, who would not willingly
throw money away, and yet what they waste in their
farm-yards they have often to pay for in hardly-earned
gold.
56. The extent to which the fermentation of farm-
yard manure should be carried depends very much
upon the character and condition of the land to
which it is going to be applied. If the land should
be a sand, or a sandy loam, the manure should be
added as short a time as possible before the crop is
going to be sown, in order that there may be less
time for it to waste away in the soil. These soils,
from their want of power to hold a manure — that is,
to preserve the manure from this wasting away — can-
not be safely trusted to take proper care of it, and
therefore it should not be added to the land until you
are going to sow a crop which will quickly make use
of it. In order that the crop may be able to use the
manure quickly, it must be ready for use, or, in other
words, the fermentation must have been carried on so
far that it has become thoroughly well rotten. The
light and free character of these soils does not admit
of their being safely rendered more open by the use
of long dung which has not been fully fermented.
57. The circumstances are just reversed in the case
of clay and clay-loam soils. These possess the power
of holding manure in safety, and they are improved in
their mechanical conditions by the use of manure
which has been but slightly fermented. Upon these
soils the fermentation of the manure may be safely
permitted to take place after its addition to the land.
^^!
t
SI
AGRICULTURE,
[CH.
58. The rapidity of fermentation is regulated by
the admission of air to the heaj) of manure. If it be
desired to make farm-yard manure ferment more
quickly, it is turned over so as to He lightly ; but
if fermentation has to be checked, it is trodden down
into a comi)act mass. The greater the rapidity of
the fermentation may be, the greater is the danger of
its throwing off its ammonia into the air, and this
renders it the more necessary in such cases to keep
it moderately moistened, so that, although it may be
a quick fermentation, it may still be kept of a right
and proper character. A proj)erly controlled fer-
mentation will preserve the ammonia ; but if it be
neglected, the most valuable constituent of the manure
will be thrown into the air.
CHAPTER V.
1 1
r
!i
ARTIFICIAL MANURES.
59. The term artificial manure is one of recent
adoption and is confined almost entirely to fertilizers
which have been brought into use within the last forty
years. Some of these are natural products, as guano
and nitrate of soda; others are manufactured, as super-
phosphate of lime and sulphate of ammonia. This
term is not applied to such manures as lime, chalk,
marl, and others of ancient use : these may be con-
veniently termed natural manures. Thus beside the
farm manures we shall have two classes, viz., the
artificial and the natural manures.
60. The first step towards the introduction of
artificial manures was the use of bones. These
were broken so as to pass through a sieve having
a mesh of half an inch. They were and still are
known as " half- inch bone." The use of these bones
upon dairy pastures had a surprising effect, and they
[CH.
ted by
f it be
; more
y ; but
1 down
dity of
nger of
nd this
o keep
may be
a right
led fer-
if it be
manure
v;
BOyES AS A MANURE.
33
)f recent
ertilizers
last forty
as guano
as super-
fa. This
le, chalk,
be con-
leside the
viz., the
action of
These
ve having
, still are
ese bones
, and they
were therefore used with great profit. It is easy to
understand why such good results followed their use.
These lands had been used for feeding cows for
many generation*. Any herbage consumed by these
cows would be robbed of its phosphoric acid,
because the animal required a supply of phosphate
of lime for the formation of milk, and for the
growth of the young calf, and a very little would be
returned to the soil in the excrements. If we ex-
amine the composition of milk we find that there is
I lb. of phosphate of lime in about 25 or 30 gallons
of milk, and it may be fairly calculated that the annual
demand upon the land for each cow is equal to 80
lbs. of bone. There was, therefore, a deficiency of
phosphate of lime consequent upon this long-continued
removal from the soil; and when bone was supplied,
lands which had become almost valueless, suddenly
became rich and luxuriant.
61. The use of bones was also extended to tillage
land, and with equally satisfactory results. Large de-
mands are made upon the soil for phosphoric acid
(41) by its continued removal in corn crops, and by
sheep and other live stock, and as these had caused a
deficiency upon ploughed lands, Hke that we have
already noticed upon the dairy pastures, similar bene-
fits were gained by the application of bones. The use
of bone thus became a settled practice, and was found
to be highly remunerative.
62. The next step in the use of bone was its reduc-
tion to a fine condition, and it was in that form sold as
bone dust, for although it was by no means as fine as
dust, it received that name. The chief difference was
the additional labour of grinding it smaller, so as to
pass through a finer sieve, but the effect upon the land
was marked by its more rapid action.
63. With a view of attaining still greater rapidity of
action bones were frequently " fermented." This was
accomplished* by putting half-inch bones into a heap,
%
AGRICULTURE.
[CH.
%
moistening them with water, and then covering them
up with sawdust or fine earth. In a short time these
bones became very warm, and when they had been so
treated for a few weeks they were found to have be-
come softened, and when used upon the land they
quickly broke up and mingled with the soil. Hence
they were more quickly ready for supplying phosphate
of lime to the plant.
64. It is very desirable that you should be acquainted
with the changers that took place in bones so employed,
and observe the chemical changes which prepared
them for absorption into circulation as plant food. In
order that you may fully realize these changes, you
must understand that there are at least three distinct
forms of phosphate of lime, and their composi-
tion may be familiarly represented in the following
manner —
Composition of
Tri-Calcic
Phosphate
Composition of
Bi-Calcic
Phosphate
Composition of
Mono-Calcic
Phosphate
Phosphoric acid.
Lime.
Lime.
Lime.
Phosphoric acid.
Lime.
Lime.
Water.
Phosphoric acid.
Lime.
Water.
Water.
You will observe the connection between their names
and their composition. The tri-calcic phosphate,
or, as the name signifies, three-lime phosphate — has
three equivalents of lime combined with one
equivalent of phosphoric acid. The bi-calcic phos-
phate, or two-lime phosphate, has only two equiva-
lents of lime with one equivalent of phosphoric acid,
ar>d one equivalent of water takes the place of the one
equivalent of lime, in which it is deficient. The
mono-calcic phosphate, or one-lime phospate,
has only one equivalent of lime combined with
one equivalent of phosphoric acid, b*it it has two
[CH.
g them
e these
3een so
ave he-
ld they
Hence
3Sphate
uainted
ployed,
repared
od. In
5es, you
istinct
omposi-
)llowing
ION OF
ALCIC
ATE
acid.
V.J
PHOSPHA TES OF LIME.
%%
names
)sphate,
te — has
th one
C phos-
equiva-
ic acid,
the one
. The
ospate,
d with
■las two
equivalents of water to make up the deficiency of
lime.
65. You will also carefully note that in each case
we have three equivalents of base combined with
the one equivalent of phosphoric acid. In one case
lime is the only base, in the two others they consist of
lime and water, but in each case there are three
equivalents of base. Hence, phosphate of lime is fre-
quently spoken of as a tri-basic phosphate, or a
three-base phosphate. I have gone somewhat fully
into these details, because if you clearly under-
stand these terms, you will 'be the better able to
trace the many important uses which' these three
phosphates of lime serve in the nutrition of our
crops.
66. We are now in a position to follow out our ex-
planation of the changes which take place in bones
after they have been applied to the soil. The phos-
phate of lime present in bones is the tri-calcic
phosphate. When the bones are acted upon
in the soil by rain water, which, as you know, con-
tains carbonic acid — or when acted upon by the car-
bonic acid, produced in the soil — in each case
we get one equivalent of the lime removed by the
carbonic acid, and the tri-calcic phosphate acted upon
then becomes bi-calcic phosphate and car-
bonate of lime. The bi-calcic phosphate dissolves
gradually in water, and is thus taken up into the cir-
culation of plants in a soluble form. The changes in
the size and condition of the bones which have been
mentioned as being adopted (60, 62, 63) all helped in
various degrees to promote their decomposition. The
action of the carbonic acid and water was greater when
the bones were broken into small pieces, because a
larger surface was thus exposed to their influence.
The fermented bones were quickly acted upon in the
soil, because by this fermentation they had been made
soft, and consequently they soon broke up in the soil
•I
86
AGRICULTURE.
[CH.
'-t\
■l
II
The carbonic acid of the atmosphere carried into the
soil in the rain-water, and any which might have been
produced in the soil, helped to make the bone more
rapidly soluble. The folIoAving diagram shows the
action of the carbonic acid upon the tri-calcic phos-
phate in bone —
Composition of
Tri-Calcic Phosphate.
Re-agrnt
Employed.
Products OF
Decomposition.
Phosphoric acid. \
Lime. >■
Lime. )
Lime.
Water.
Carbonic acid.
Bi-calcic phosphate.
Carbonate of lime.
67. Up to 1840 phosphate of lime was added to the
soil by the use of bones, having varying degrees of
fineness; but, in that year, Liebig proposed a chem-
ical treatment of bones, whereby they were
rendered more rapidly soluble, and consequently were
ready for use for the crop with less loss of time. In
fact, instead of the farmer having to wait some months
for any general action of the bone, this (shemical
treatment made the bone ready for immediate use.
Liebig's discovery of the means whereby these results
could be attained with such promptitude, was---like
many other great discoveries — exceedingly simple* He
imitated the natural decomposition of bone as it takes
place in the soil, but he accomplished the work more
q'dcklj by using a stronger acid. We have seen (66)
that the carbonic acid slowly and quietly took from
the tri-calcic phosphate some of its lime, and thus in-
creased the solubility of the bone, but Lrebig used
sulphuric acid, which is a very powerful acid, and this
accomplished in one hour more than the carbonic acid
could do in one year. The chemical change was
practically completed at once, and the phosphaie of
lime in the bone became immediately soluble in
water.
r
,
v.]
SUPER^PHOSPHA TE OF LIME.
Vt
68. But Liebig's process did something more than
gain time — he obtained the tri-calcic phosphate of the
bone in a thoroughly soUible condition, and in this
respect the chemical change he accomplished
went beyond that wfiich naturally occurred
in the soil. The difference will be more clearly under-
stood by reference to the following diagram: —
Composition of
Tri-calcic Phosphate.
Re-agent
Employed.
Products OF
Decomposition.
Phosphoric acid. )
Lime. )
Lime. )
Lime. )
Water. )
Water. \
Sulphuric acid.
Mono-calcic phosphate.
Sulphate of lime.
69. If you compare this diagram with that immed-
iately preceding it, you will see that a different form
of phosphate of lime is obtained from that
which had been produced in the soil by the slow
decomposition of the bone. In the former case
a bi-calcic phosphate was produced, and this is a
slowly soluble phosphate of lime. In the latter
case we have mono-calcic phosphate produced, and
this is rapidly soluble in water.
70. The treatment of bone by means of sulphuric
acid thus introduced by Liebig therefore produced
a new kind of manure, which has been distinguished
as super-phosphate of lime. You will readily
understand that it was called Super-phosphate of
lime, because the phosphoric acid which had been
combined with three equivalents of lime had been
concentrated upon one equivalent of lime, and the
lime was thus super-phosphated, or, in other
words, the lime was over-charged with phosphoric
acid. It must be remembered that not only is mono-
calcic phosphate thus formed, but a large quantity of
sulphate of lim? is also produced by the action of the
sulphuric acid oa the bone, and consequently the
38
AGRICULTURE,
[CH.
1?
" super-phosphate of lime" is really a mixture, of which
the active ingredient — mono-calcic phosphate — forms
sometimes not more than one-fourth of the entire weight.
71. This discovery of Liebig's led to the establish-
ment of an entirely new branch of chemical manufac-
ture, for although for a time farmers manufactured
their own super-phosphate, by purchasing bones and
suphuric acid, it was soon found that a manufacturer,
with convenient machinery, could do the work far
more advantageously and economically. The late
Mr. Thomas Proctor of Bristol was the first manufac-
turer of super-phosphate of lime. He was present at
the meeting of the British Association when Liebig
announced his great discovery. As soon as it was
made known he travelled to Bristol with all speed,
and at once commenced the manufacture, promptly
sending out Liebig's new manure ready for use. The
economy of the new process was soon recognized,
and the manufacture of artificial manures advanced
with incredible rapidity.
72. The next advance was the discovery of Mr.
J. B. Lawes.in 1842, whereby he proved that mineral
phosphates of lime were capable of being manu-
factured so as to produce the same mono-calcic
phosphate, which had previously been manufactured
solely from bone. This led to an extensive
search for rocks, and other mineral deposits contain-
ing the tri-calcic phosphates, and the result has been
a considerable decrease in the cost of the materials
used in the manufacture, which has resulted in a
cheaper supply for the farmer's use. The new
description of super-phosphate of lime thus introduced
was distinguished as mineral super-phosphate,
that is to say, super-phosphate of lime manufactured
from mineral phosphates. Subsequent experience has
confirmed Mr. Lawes' original opinion, and has
resulted in super-phosphate of lime being now very
ade by the judicious use of mixtures of
largely
[CH.
v.]
MtMERAL SUPERPHOSPHA TdS.
99
mineral phosphates and bone, whereby economy of
manufacture has been coupled with high quaHty.
73. Another source of phosphate must also be
noticed, and that is known as bone ash. This has
been largely imported from South America, and is the
ash of the bones, used for fuel to melt the tallow
obtained from the herds of cattle slaughtered for their
tallow, hides, and horns. Many thousand head of
cattle were thus slaughtered, and as fuel was scarce,
the bones were so employed. For many years the
ash was not of any value, and immense quantities had
been accumulated, when the bone ash suddenly be-
came of great value by reason of its new use for the
manufacture of super-phosphate of lime. Bone ash has
since then been found valuable for many other manu-
factures.
74. It has been explained {(i(i) that bi-calcic
pliosphate is produced in the soil by the gradual
decomposition of bones, and it may be added that the
growth of vegetation arising from this use of bones is
always of a most healthy character. Liebig's
important discovery, which was intended to obtain
the same results more rapidly, has been made use of
very extensively, but it has been recognized that we
have to a great extent " over-manufactured" our phos-
phate by converting it entirely into a mono-calcic
phosphate. This more rapid process has not, how-
ever, accomplished the same result, and the un-
healthy character of vegetation often testifies to this
fact.
75. There is every reason to believe that the mono-
calcic phosphate, by reason of its solubility, is easily
distributed through the soil, but that it is too acid in
its character to enter into the circulation of plants.
If a manure containing mono-calcic phosphate be
added to a calcareous soil, the lime with which it
comes in contact combines with it, and the mono-
calcic phosphate becomes changed into a bi-calcic
' i
40
AGRICVLTVRR.
(cH.
V.
M
phosphate, which gradually enters into the circulation
of the plant. The presence of lime in a soil, even in
a small proportion, accomplishes this result, and by
reason of the less soluble condition to which it is thus
reduced, there is also less danger of the phosphate
being washed out of the soil. On many light sandy
soils the use of ordinary super-phosphate is attended
with great loss, as the mono-calcic phosphate is washed
out of the soil, by the rain passing through it. In
these cases the use of bone is still found the most
economical form for adding phosphate of lime to the
soil, as this waste is thereby prevented.
76. It is, however, quite possible for the form of
phosphate produced by the action of sulphuric acid on
bone or other phosphates to be of the same character
as that produced by the decomposition of bones in
the soil. By the use of one-half of the sulphuric acid
required to make mono-calcic phosphate, we obtain
the same form of phosphate of lime as is produced in
the soil when bones decompose in the ordinary
manner. It is, as we have seen, a more desirable
form of phosphate, so far as the healthy growth of
vegetation is concerned, and it is by no means, im-
probable, and much to be desired, that circumstances
may shortly lead to its more extensive use.
77. One other subject, closely associated with
super-phosphate, demands notice in passing, viz., the
'^ reduced phosphates.*' When a manufacturer
has made a large quantity of super-phosphate, and has
ascertained its strength by analysis, it very frequently
happens that after a lapse of two or three months the
super-phosphate is found to be reduced in strength
It is then known as a reduced super-phos-
phate. A super-phosphate having 25 per cent, of
soluble phosphate is often found to be reduced to 22
or perhaps to 20 per cent. If the value of this super-
phosphate were to be determined by analysis, the
manufacturer would lose largely, because chemists
fc«r.
v.]
• 'HED UCED SVPER-PmSPHA TES. "
4t
base their estimates of the value of super-phosphates
upon the quantity of soluble phosphate which they
contain. As a matter of fact, manufacturers and
many farmers know that the reduced super-phosphates,
instead of being of less value, are really of greater
value for the land^ and will'be found more valuable
fertilizers than before the reduction took place. This
appears a somewhat contradictory statement until the
cause of reduction is known. The simple fact is that
the mono-calcic phosphate wTiich was present in the
super-phosphate in the first instance, is diminished in
quantity by a portion being changed into the form of
bi-calcic phosphate, and this portion which has be-
come so changed is no longer estimated by analysis
as a soluble phosphate. All that has been so changed
in character represents so much loss to the manufac-
turer, if he sells simply on the basis of the soluble or
mono-calcic phosphate present. At the same time it
means an actual increase in the value of the manure,
for those farmers who use these " reduced super-phos^
phates" find that they are generally most lasting
in their action and altogether more valuable man-
ures.
78. This "reduction of super-phosphates" may be,
and is produced artificially, by an admixture of finely-
pulverized bone. Some of the highly-soluble phos-
phate is thus reduced to the slowly-soluble form, and
yet the fertilizing power of the manure is increased.
Here, as in the case of the reduced super-phosphates
already referred to, there would be a serious loss to
the manufacturer, if the value were determined by the
present system, and accordingly this very useful prac-
tice is discouraged.
79. In the purchase of super-phosphate of lime it
is usual for the strength to be described by saying that
it contains a certain percentage of soluble phos-
phate. As this is a term commonly used in every
market town in the couuiry, you should clearly under"
42
' AGRICULTURE.
[CH
Stand what is meant by it. Soluble phosphate is only
another name for mono-calcic phosphate, which has
been already described as being rapidly soluble in
water. If a portion of superphosphate of lime be
added to a proper quantity of water, and especially if
tepid water be employed, in a few hours the whole of
the mono-calcic phosphate is dissolved out of it.
Thus the soluble phosphate is separated from the rest
of the manure, and its quantity is estimated by
chemical analysis.
80. Purchases are frequently based upon the
strength of the super-phosphate, which is often sold as
containing, say 25 per cent of soluble phosphate. It
would of course be a perfectly reasonable contract
that a super-phosphate of lime should contain say
25 per cent, of soluble or mono-calcic phosphate, but
in the great majority of cases something different from
this is really intended. The strength intended is more
correctly stated when expressed as equal to 25 per
cent, of tri-calcic phosphate rendered soluble.
You may take it that 20 cwt. of tri-calcic phosphate
rendered soluble will only yield about 15 cwt. of
soluble or mono-calcic phosphate, so that 25 per cent,
in the trade sense, viz., 25 per cent, of tri-calcic phos-
phate rendered soluble, really means only 19 per cent,
of soluble or mono-calcic phosphate in the sample.
81. It may be convenient to notice at this stage the
practice of selling manures upon the " unit System,'*
which is becoming more and more general, viz., a
sale of super-phosphate at an agreed price per unit.
When a super-phosphate is thus sold which contains
25 per cent, of tri-calcic phosphate made soluble, this
represents 25 units at the agreed price, it may be
3s , 4s., or more per unit, per ton. If it contains
30 per cent, this would represent 30 units, and thus
the number of units always corresponds with the
amount per cent. A super-phosphate containing 25
units and sold at 4s. per unit would produce £^% per
[en
v.]
yAL(/A r/ON" OF MA INURES.
49
It
.
ton; or if it contained 30 units at the same price per
unit, it would be ^6 per ton, and so on. It is on this
basis that the valuation of manures has been
established. Experience, however, has shown that
great care is necessary in making these valuations.
One difficulty exists in fixing the price per unit, but
this is necessarily subject to the variations of the
market, and is a fair matter for contract as between
buyer and seller.
82. It will be easily understood from what has been
said that the method of valuation indicated above
(7 7) is somewhat defective, for whilst the bi-calcic phos-
phate is a most useful part of the manure,the valuer pays
attention almost entirely to the mono-calcic phosphate,
because the estimation of the former is somewhat diffi-*
cult, and its value has not yet been fully appreciated
by chemists. This is a matter of considerable impor-
tance; for so long as the present system of vahiation is
maintained, so long manufacturers will be compelled
to sell, and farmers to buy, over-manufactUred
manures, having a higher degree of solubility than
is consistent with the healthy growth of our crops.
On the other hand, the production of a form of phos-
phate whose high value is well known to the farmer
and the manufacturer, is now rendered practically
impossible. The magnitude of this question will be
more fully realized when you consider that 'the sales
of super-phosphate represent an annual outlay of be-
tween two and three million pounds sterling.
83. There is another class of artificial manures
which are chiefly disti'nguished by the presence of
nitrogenous compounds. Peruvian guano is
one of the richest manures of this class. Its value
depends not only upon the large quantity of ammonia
which it contains, but upon the fact that it is mixed
with various other valuable fertilizers. Guano is the
dung of sea-birds, which has accumulnted for many
centuries in a climate where there is but little rain to
44
AGRICULTURE.
[CH. I v.l
injure it. It was first imported into England in 1839,
and at that time the supply in Peru was very large,
some of the beds being fully 200 feet in depth. Many
millions of tons have been imported since that time,
and the quality is not so good now as it used to be.
An average of fifty cargoes, imported into England
before 1855, contained nitrogenous matter equal to
rather more than 17 per cent, of ammonia. At the
present time, it may be taken as containing nitrogen-
ous matter equal to about 8 or 10 per cent, of am-
monia. Peruvian guano also contains a large quan-
tity of phosphates in an exceedingly valuable form,
and these add to its value.
84. In 1864, Dr. Voelcker recommended the treat-
ment of Peruvian guano by the use of a small per-
centage of sulphuric acid, with the twofold object of
rendering the ammonia it contained non-volatile, and
of making the phosphates more quickly soluble in
water. The first was accomplished by the sulphuric
acid combining with the ammonia, and forming sul-
phate of ammonia. The second change arose from
the phosphate being converted into mono-calcic phos-
phate in the manner already described (68). This
treatment of Peruvian guano was commenced on the
continent in 1864, by Messrs. Ohlendorff, and has
since then been very largely carried on in England —
the manufactured article being sold as " Dissolved
Guano."
85. Sulphate of ammonia is another nitrogen-
ous manure which is very largely used in this country,
and which exerts as great an influence as a fertilizer
as the Peruvian guano, if not greater. This is pre-
pared from what was once known as the waste liquor
of gas works. It is a waste liquor no longer, as it is
carefully sought after for the production of sulphate
of ammonia. This manure is a white crystalline sub-
stance, more or less discoloured by impurities, and is
obtained by first addmg sulphuric acid to the gas
few. I v.]
NITRA TE OF SODA,
gJand in 1839,
I'as very large,
depth. Many
nee that time,
t used to be.
into England
itter equal to
onia. At the
»>ng nitrogen-
cent, of am-
Jarge quan-
iluable form,
ed the treat-
a small per-
)ld object of
volatile, and
' soluble in
^e sulphuric
orming sul-
arose from
calcic phos-
(68). This
[ced on the
^» and has
England—-
Dissolved
■ nitrogen-
s country,
. fertilizer
is is pre-
ste liquor
-r, as it is
sulphate
liinesub-
ss, and is
the gas
liquor in sufficient quantities to combine with the
ammonia, after which the sulphate of ammonia is
crystallized in the usual manner. The chief bulk is
employed by the manufacturers of artificial manures,
who fully understand its value, and use it in proper
combination with other fertilizers. Its value depends
upon the percentage of ammonia which it contains.
86. Nitrate of soda is an exceeding popular
manure of the same class. It is a nitrogenous manure ;
but it does not contain ammonia like the two preced-
ing manures. Here the nitrogen is present as nitric
acid, and this is combined with soda. It is a very
powerful manure, of a white crystalline appearance.
It is largely imported from Peru and Chili, where it
exists as a crust near the surface of the land. This is
therefore a second and very important manure which
we receive from Peru. Nitrate of soda is largely used
for manufacturing purposes, besides being employed
for making artificial manures. Farmers have the
advantage of being able to supply their requirements
by the use of other nitrogenous materials, when the
supply of nitrate of soda is scarce. For other manu-
facturing purposes, nitrate of soda is actually neces-
sary. The demand for these uses therefore takes the
precedence by the supply being secured, even at ar\
advanced price. Its agricultural value is usually
determined by calculating the nitrogen it contains, as
equal in value to the same quantity of nitrogen in the
form of ammonia ; that is to say, the nitrogen, whether
in the form of a nitrate, or in the form of ammonia,
is usually taken as of the same market value.
87. Another source of nitrogen for fertilizing pur-
poses is the employment of WOOllen waste,
shoddy, also dried flesh and blood, fish re-
fuse, rape dust, seaweed, &c. These all
contain a large percentage of nitrogen, which by
decomposition can be converted into ammonia.
They render convenient supplies of ammonia to the
46
AGRICULTURE,
[CH.
\
*
plant through its several succesiiive stages of growth
by the slow and gradual formation of the am-
monia. We have referred to the fact (56) that
many soils have little power for retaining ammonia
when it is added in a soluble form, and from these
soils much is lost by using ammonia in such a form,
for instance, as the sulphate of ammonia ; whereas,
by selecting fertilizing substances which will supply
ammonia slowly by their gradual decomposition, the
growing crop has a better opportunity for using it
without waste.
88. Potash exercises an important influence in
promoting the fertility of the land. The nitrate of
potash, which is a most powerful manure, always com-
mands a price considerably higher than nitiate of
soda, because the former is used for the manufacture
of gunpowder, whereas the latter cannot be so em-
ployed. Some other source of potash had therefore
to be found (107). The ashes of wood fires yielded
small supplies, and their influence upon the land was
generally very marked, but the quantity obtained in
this way was very small for the purposes of manuring
land. Some few years since large deposits of potash
salts were discovered in Germany, and they were
introduced into this country under the name of
kainite. It generally contains about 25 per cent, of
sulphate of potash. In some cases the use of potash
in this form has been productive of most satisfactory
resultS; but as a rule its use has not realized the san-
guine expectations which were so generally enter-
tained. This in noway depreciates the value pre-
viously set upon a proper supply of potash ; it rather
indicates that we have in some degree failed to employ
the kainite so as to secure the best results which the
potash it contains is capable of producing.
89. Common salt is also largely employed as a
manure. It is a compound of chlorine and sodium,
and by its use we arc enabled to supply to the soil a
[CH.
v.]
SALT AS A MAN UK E.
much-needed fertilizer — soda. The chief source of
supply is from salt-mines, such as exist so largely in
Cheshire, and also from the evaporation of sea-water.
Good samples of Cheshire salt contain as much as
98 per cent, of chloride of sodium; but the salt
obtained from sea-water usually contains chloride of
magnesium, and it is more than usually disposed to
become moist, which renders its distribution more
difficult. Its action as a fertilizer is in many respects
peculiar, by reason of its apparently inconsistent influ-
ences, for in many cases we see it giving a decided
check to vegetable growth, and yet thereby increasing
the production of corn. For some crops, such as the
mangel wurzel, salt is a direct requirement of the
plant as food. Beans, cabbages, and onions also
appear to flourish with liberal supplies. The analysis
of the ash of mangel wurzel shows considerable varia-
tion in the quantity of salt present. According to
Way and Ogston the average of four analyses of the
bulb showed a variation of from 10 per cent, to 4951
per cent, of salt in the ash, and an average of 24*55
per cent. The tops of the mangel wurzel, on the
same authority, contained 33*96 per cent, of salt in
the ash. It is therefore evident that this crop in
particular requires a supply of salt as plant-food. It
is present in the ash of every cultivated plant, and it
must therefore be regarded as generally desirable as
a food for these crops. The necessity for supplying it
to the land will be determined in a great measure by
the supply already existing in the soil. Lands which
are situated near the sea have a supply carried by
winds from the sea, and the quantity of salt which is
thus carried inland for twenty, thirty, or sometimes
even forty miles, will surprise those who have never
tested this supply. '
90. One important influence which salt exerts on
vegetation arises from its power to check plant
growthi possibly arising from the action of the
U'
48
AGRICULTURE,
[CH.
1
chlorine which it contains. Whatever may be the
direct cause, it is evident that we have m salt an
agency which can be used to check the growth, even
up to the extent of destroying the life of the plant.
This is a most important agency, and w hen more fully
understood will be more generally utilized. In the
processes of cultivation, the necessity for this influence
often arises. Take, for instance, our corn crops. If
the land be too highly manured, these crops have a
tendency, to produce straw rather than corn, the grassy
character of the plant being thus unduly encouraged.
Th's growth of the straw is often too rapid to allow of
the plant bringing up the necessary supplies of mineral
matter, for securing a strong straw. The first disad-
vantage is seen in a large growth of weak straw, which
has not sufficient strength to stand whilst the seed
is being formed. If this difficulty should be sur-
mounted, then this tendency to continue the growth
of straw, often prevents the formation of a good ear of
corn. Every farmer knows the dangers resulting
from an overgrowth of straw; but whilst avoiding this
danger, it is generally desirable for him to have his
land in such high condition that he may be safe for a
good crop of corn. He has therefore to adopt such a
medium course, as local experience indicates to be
most likely to secure a good produce of corn, without
an overgrowth of straw. An unusually wet season,
however, frequently upsets the best calculations, the
crop suffers, and yields an inferior quality of corn.
Salt is frequently found valuable in such cases, by the
check it gives to the growth of straw, and the greater
strength gained by the straw in consequence of this
impeded growth. It may therefore be generally
considered as shortening and strengthening the
growth of the Straw.
91. In like manner, when nitrate of soda has been
freely used upon growing corn, there is an energetic
growth of the straw, which continues duiing ilie for-
V.
m
st
CO
th
im
[CH.
y be the
salt an
vth, even
he plant,
lore fully
In the
influence
:rops. If
s have a
he grassy
ouraged.
) allow of
f mineral
St disad-
w, which
the seed
be sur-
e growth
od ear of
resulting
ding this
^ave his
afe for a
)t such a
to be
without
season,
ons, the
)f corn.
, by the
greater
of this
merally
ng the
is been
ergetic
he for-
v.r
SPMCIaL MANURES,
40
mation of the corn, so much so in some cases as to
give the ear the appearance of having been over-
stretched, the spaces between the several grains of
corn being larger than usual. When this happens,
the production of a good crop of corn is extremely
improbable. In such a case as this, the influence of
salt would have been most valuable, as ittfvould have
checked the excessive growth of straw, and thereby
encouraged the growth 6f corn. It does not prevent
the nitrate of soda exerting its full fertilizing power,
but it appears to exercise a controlling influence,
whereby that power is more satisfactorily utilized.
There are, however, exceptional soils, "on which there
is not the slightest fear of producing too much straw
by any ordinary use of manure; to these cases we are
not making reference. Our remarks illustrate the
action of salt in those cases where the character of
the soil, or the employment of a stimulating nitro-
genous manure, favour high cultivation, whilst the salt,
acting as a "brake to the carriage wheels," renders a
quick pace much more safe.
92. The tendency which salt exhibits to attract
moisture from theatm.osphere in some degree influ-
ences its employment upon light lands, but for this
purpose a salt known as " hide salt" is specially
valuable. Foreign hides are often salted for ship-
ment to this country, and the salt so used is sold as
manure when the vessels are discharged. This salt
has by this employment become impregnated with
animal matter, which adds to its value as manure.
93. Special Manures. These are a class of
manures specially prepared for various crops. Each
manufacturer supplies that fertilizing matter which he
considers best for any particular crop, and he supplies
it in that form, and in that association, which his
experience leads him to consider to be most likely to
produce the best crop. These are generally sold
without guarantee as to strength, or percentage oC
50
AGRICULTURE.
tett.
II
solubility, and give the manufacturer free scope for
the exercise of his judgment. As a rule, very great
excellence has been attained by the careful researches
carried out by the manufacturers, and by the purchase
of the best materials at the lowest prices. Their
opportunities for watching the results of their several
trial manufes are unusually good, and it is to their
interest to observe these results, and carefully note
instances of success and failure. It is just as they
succeed in manufacturing a successful manure, that
their public reputation will stand or fall on the
market. It must be admitted that they have done
much; but, on the other hand, if farmers had a fuller
knowledge of what they were using, they also would
be observers, and would soon point out which of the
several constituents could be lessened, and which
could be advantageously increased, so as to suit their
own farms, or certain recognized portions thereof.
The manufacturer, to secure a general success, has to
provide for all the requirements likely to arise, and
thus provision is unavoidably made for many require-
ments which do not arise. The farmer has thus to
pay for some unnecessar); supplies, whereas, just in
proportion as he knows what he is using, and watches
the influence of variations made by way of experi-
ment, so he ultimately gets to know what his farm
requires, and thereby he avoids purchasing that which
is not necessary.
It is by carrying out experimental trials in
different neighborhoods that this information will
be best obtained, and in this way variations in soil
and climate may be most judiciously and economi-
cally dealt witii.
i
%:
1^
LIME AS A MANURE.
! : n CHAWER VI. 'iV:
NATURAL MANURES.
St
:-i ■■ ' •
,\t
94. Lime ranks as one of the most Important
manures at the farmer's command, and its use dates
from very early periods of time. It exists very abun-
dantly in many of our rocks, as in our limestone and
chalk formations, in the form of carbonate of lime,
which is a compound of carbonic acid and lime. 11
is also found in rocks as sulphate of lime, or gypsum,
which is a compound of sulphuric acid and lime. In
this form it is far less abundant than as carbonate of
lime. There is another supply of lime found in com-
bination with phosphoric acid as phosphate of lime,
but this exists in a still more limited quantity. This
is howe". r a very valuable manure, and is carefully
sought t'^i ^ aerever it can be easily raised and con-
veyed tc J 1 >rt for shipment. In the West Indies,
Spain, Portugal, Germany, Carolina, &c., very large
quantities are raised, and sent to England for the
manufacture of manures. Considerable quantities
are obtained in England, in the form of coprolites;
but the present supplies are inferior in character to
those at first raised, and they scarcely compete with
the foreign supplies of high-quality phosphate of lime,
which are now so largely used.
95. The use of lime as a manure is practically
limited to the employment of various forms of car-
bonate of lime, either in a natural or prepared
condition. It is true that in combination with
sulphuric acid and phosphoric acid it is added to
the soil, but the sulphate of lime and the phosphate
of lime so employed are used for the sulphuric and
phosphoric acid they contain, rather than for their
lime. The carbonate of lime must be regarded as the
source of the lime used for the purpose of manure,
it
'. f
82
AGRICULTUnE.
[ctf.
96. The action of lime as a manure is entirely
regulated by the form and manner in which it is
employed. It is very desirable for these variations
in practice to be distinctly understood. The form
in which lime is most largely employed is as burnt
lime« In its preparation, limestoiie or chalk rock
is placed in a kiln, with some fuel, and after an expos-
ure to the fire thereby produced, we find the " lime"
has changed its character and its composition. The
carbonic acid wh^ch was present has been driven off,
it is therefore no longer a carbonate of lime, but lime.
It is sometimes called quick lime sometimes burnt
or calcined lime, or caustic lime, but you must
remember that it is no longer a carbonate of hme,
because the carbonic acid has been driven off.
97. The burnt lime is very different from the lime-
stone or chalk rock, as you will readily see if you
take a lump of each, and put some water upon them.
The limestone and chalk are not changed by the
water, but with the burnt lime it is very different.
A violent action takes place, which produces much
heat, and breaks the burnt lime into a fine powder.
This is commonly known as " slaking the lime,"
but viewed from a chemical point of view, the change
which has taken place is a combination of the water
with the lime. It is not simply a mixture of the
water with the burnt lime, wM.-h would only have the
effect of wetting the lime, bui a definite union has
taken place between the water and the lime, and a
new product is obtained, viz., hydrate of lime, or,
as it is more commonly known, slaked lime.
98. If this slaked lime is allowed to remain exposed
to the air, the carbonic acid of the atmosphere readily
enters into combination with it, and we have carbonate
of lime again produced. Carbonic acid, which we
drove away by burning in the kiln, again associates
lime, and the practical change which
is the reduction of the carbonate of
has
j)U
VI]*
ACTION OF BURNT LIME,
S5
is entirely
which it is
e variations
The form
is as burnt
chalk rock
er an expos-
the "lime"
ition. The
n driven off,
ne, but lime.
imes burnt
t you must
ite of lime,
n off.
)m the lime-
' see if you
upon them,
ged by the
ry different,
duces much
ine powder.
:he lime,"
the change
'f the water
ture of the
nlyhave the
union has
lime, and a
f lime, or,
ime.
lin exposed
lere readily
e carbonate
, which we
associates
inge which
irbonate of
lime from its original rocky condition into a fine
powder. By this reunion of the carbonic acid with
the lime it has now lost its caustic character, it has
ceased to be a caustic lime, it has again become
carbonate of lime. You will find that if you clearly
understand these simple changes in the character of
lime, that you will easily distinguish the special ad-
vantages which are to be gained by the use of burnt
or caustic lime upon the land.
99. The org^anic matter in a soil is rapidly
acted upon by burnt lime. We have already
noticed that the slaked lime quickly draws the car-
bonic acid of the atmosphere into combination with
itself, and the same action takes place in the soil; for
when the organic matter undergoes decomposition,
carbonic acid, or some form of organic acid, is pro-
duced and is immediately seized by the lime. This
action favours the more perfect decomposition of that
organic matter which remains, and as rapidly as the
presence of air or moisture permits, fresh food is
provided for the lime to lay hold of. The harsh
and hungry character of the lime which we called
its caustic character soon becomes satisfied by the
carbonic acid or other organic acid, and it forms a
mild and gentle ingredient of the soil, in the form of
a carbonate or other salt of lime.
100. In some soils we find a large quantity of these
organic acids, existing in them to the great injury of
the land, and these soils are well known as being
" sour." A farmer who has no knowledge of
chemistry will tell, quite as accurately as a chemist,
when a land is sour, for he judges by the character of
the herbage growing on the surface. This herbage
is always harsh, and of little value as food. When
the mower cuts it with his scythe, he soon finds the
cutting hard and difficult, for his scythe quickly loses
its sharp edge, and he tells his master that the land is
sour an4 wants lime. The beneficial action of lim«
54
t%
AGRtCUL TURE. ^ --
[Clt.
SB S
in such a case as this, you will readily understand,
arises from the lime combining with these organic
acids, which make the land sour, and turning them
into a condition in which they are, to say the least,
harmless; for the acid or sour bodies present have
been neutralized.
loi. This removal of the sourness of land is some-
times described as a sweetening of the herbage.
The two terms practically represent the same change,
for when by the use of lime this sourness of the land
has been corrected, we find a sweeter and better
quality of herbage produced, and the stock in the
field prefer it.
1 02. In such cases as this the burnt lime acts very
quickly upon the organic acids in the soil, and in per-
forming its work it shows great energy of action. This
has led to its being called quick-lime, in distinction
from the dead and inactive forms which lime assumes
after its work has been performed. You should, how-
ever, remember that burnt or calcined lime, caustic
lime, and quick-lime, are all different names for the
form of lime which is drawn fresh from the lime kiln.
103. Burnt lime also acts upon the inorganic mat-
ter of the soil, and in many cases it liberates potash
and soda from the dormant matter of the soil, and
renders them available for vegetable growth.
104. Its most important action on this portion of the
soil is probably in the assistance which it renders for
the formation of the double silicates of alumina.
These we have already noticed (24) as having a very
important influence upon the fertility of the land. It
has been stated that there are four of these double sili-
cates of alumina which have been described as silicates
of alumina in which part of the alumina is replaced by
lime, soda, potash, or ammonia. You are probably
ftware that ammonia is more v lu • le than potash,
whilst potash is of more value iha. lime, and lime is
of mortj vi^lue than soda, The silicate Qf alumina
tJt»i^ m * -'mn \ M w i i) iitt lMH i fr%i. ^ - **-— =
VI.]
PRODUCTION OF NITRE.
55
lie, caustic
appears to exercise a similar order of preference. If a
double silicate of alumina and soda exists in the soil,
and lime should be brought in contact with it, the
silicate of alumina gives up the soda and takes up the
lime instead, and thus we get silicate of alumina and
lime. The presence of soda will not enable it to dis-
place the lime, as the silicate of alumina prefers the
lime to the soda. If, however, some potash be added,
the lime is given up and the potash is taken into com-
bination, because the silicate of alumina prefers the
potash, and thus we obtain siHcate of alumina and
potash. But if ammonia comes within the influence
of this compound, there is so much preference for the
ammonia, that even the potash loses its position, and
then we get silicate of alumina and ammonia formed.
105. The chief difficulty, as far as we know, appears
to be in getting the silicate of alumina to commence
taking in one of these substances. If by any means
you can produce even the lowest form, viz., the double
silicate of alumina and soda, there is no difficulty in
advancing through the higher stages. The real diffi-
culty is in the commencement of the series. In this
respect the energy of the caustic lime appears to be
very valuable, and thereby the double silicate of
alumina and lime is probably produced. The special
action that caustic lime, which has been slaked with
water containing salt, has upon silicate of alumina,
favours this view. We may, therefore, regard the ac-
tion of caustic lime upon clay — which latter sub-
stance, you will remember, consists very largely of
silicate of alumina, as contributing to the production
of that most valuable class of bodies which have been
called the double silicates.
'06, Caustic lime also favors the production of
nitrate of potash in the soil. This action, when it
takes place in the compost heaps of the farm, admits of
more careful observation than when the change is ac-
complisbecl ia ^h§ soil, There is, however, no reason
H
1
I' fi
*'
|6
AGRICULTURE.
[CH,
to doubt, but that similar changes take place in the
soil under like conditions. In properly constructed
compost heaps, especially where some farm-yard
manure is present, we have, in fact, a very near ap-
proach to what are known as nitre-beds — or beds of
earth constructed for the production of nitre.
107. Nitre (or nitrate of potash) is largely used for
the manufacture of gunpowder. It happened that in
the wars between England and France, in the last cen-
tury^ the British cruisers kept such a sharp look-out
for the trading vessels going to France, that there was
often a very great difficulty in getting the nitre they re-
quired for their supplies of gunpowder. In 1775, the
French government offered a prize for the best method
of producing saltpetre or nitrate of potash in that
country. The prize was awarded in 1776 to Mons.
Thouvenel, and from that time nitrate of potash has
been largely manufactured by what are sometimes
known as saltpetre plantations, and in other places as
nitre-beds. The general formation of these is very
similar. Earth is either intermixed with decaying
vegetable and animal matters, or else it is charged with
the manure from sheep, and two necessary conditions
are thus secured, viz., nitrogenous matter and earth.
After a short time chalk or marl is intermixed, and tho
decomposition which takes place leads to the formation
of nitrate of potash. When it is desired to separate the
saltpetre, it is washed out by water, and the solution is
evaporated. Care is taken to protect the nitre beds from
rain, which would wash away the niJtrate of potash, and
the earth is laid up in small heaps so as to secure the
full influence of the atmospheric air. In some cases
the lime is used in a caustic form, and by its intermix-
ture with the soil much of the potash of the soil is
liberated, before the caustic lime is converted into the
form of carbonate. Soil which has been thus prepared
and intermixed with any decaying vegetable or animal
matter is admirably adapted for the produQUQn gf
\A^
wmliw' !
\m^r^:rmr0mmmmmmitmm^
Ic«.
ice in the
onstructed
farm -yard
near ap-
t>r beds of
re.
y used for
ed that in
elast cen-
look-out
there was
re they re-
H775»the
St method
ih in that
to Mons.
)0tash has
sometimes
■ places as
se is very
decaying
irged with
;onditions
nd earth.
3, and tho
'ormation
)arate the
alution is
)eds from
tash, and
scure the
me cases
ntermix-
e soil is
into the
prepared
raTiimal
etion of
VI.1
ACTION OF CAUSTIC LIME.
57
nitrate of potash, and the quantity is largely increased
by small additions of liquid manure. These conditions
are very commonly fulfilled in the soil, and we may
therefore fairly consider that lime acting upon the
farm-yard manure, and the inorganic matter of the soil
promotes the production of nitrate of potash.
io8. We have already noticed the necessity which
exists for a supply of lime to meet the requirements
of the crops so far as regards that quantity which the
plant receives as food. Every cultivated plant
needs a supply of lime fox the proper building up ot
its structure, but some, like the beans and peas, clovef
and root crops, require it in greater abundance than
other crops.
109. The physical or mechanical action of
lime upon heavy clay soils is another feature of its
character which must not be overlooked. It makes
these soils more mellow, and therefore more easily
cultivated, at the same time it favours the admission
of air and water into the soil, with all their powers for
developing its fertility, and it gives a more healthy
character to the vegetation growing upon such land.
1 10. The advantages arising from the use of caustic
or quick-lime may be enumerated as follows: —
(i) It encourages the decomposition of the organic
matter in the soil.
(2) It neutralizes the organic acids which make land
sour, and it improves the quality of the herbage.
(3) It assists the liberation of alkaline matters
(potash and soda) from the dormant ingredients in
the soil.
(4) It promotes the formation of the double silicates,
(5) It favours the production of nitrate of potash.
(6) It contributes food essential for the perfect
growth of the crops.
(7) It improves the physical character of the soil,
and promotes healthy growth.
ThesQ ^re exceedingly important duties for any
AGRICULTURE,
> r
[CH.
manure to be capable of performing. We may now
proceed to notice how the caustic lime can be most
economically and advantageously enabled to perform
these duties.
HI. It has been already explained that some of
these duties can only be accomplished by lime when
caustic. In such cases the lime should be brought
into work with the least possible loss of its causticity.
You are already aware of the fact that the carbonic
acid of the atmosphere has a strong disposition to
combine with the caustic lime, and in doing so the
lime loses its caustic character and becomes a car-
bonate of lime. As a rule, much of the lime used as
manure is allowed to be exposed to the weather to a
very great extent before it is able to commence its
work,
112. There are two methods by which caustic lime
is slaked. One of these is a bad and wasteful
system and the other is a good and economical
plan. It is a too common practice for lime which has
been drawn for manure, to be distributed over the land
in small heaps ^ and left there until the rain has slaked
it. This not only leads to much delay, but, as the
slaking takes olace gradually, much of the lime has
been acted upon by the carbonic acid of the atmos-
phere, and much of its power lost before it is brought
mto use. Compare with this the care taken by a
mason when slaking lime for mortar: no delay is
allowed, it is done quickly by adding sufficient water,
and then it is heaped up and covered from the air by
sand. Some farmers adopt the same plan, and as soon
as the heaps are made in the field, a water cart carries
round the water required for the proper slaking of the
lime, and it is then heaped up, and protected from the
air by a covering of earth. For building purposes it
is necessary to slake the lime thoroughly and wittiout
loss, and it is equally so for use as a manure. The
p^ily diOfer^i^qe is that %^ lo§§ is mpr^ easily d^t^gt§4
VI.]
ECONOMICAL USE OF UME.
n
in the case of the builder, but it is equally a loss to the
farmer whether he knows it or not. Lime is, after all,
an expensive manure before it is got upon the land,
and it is unwise to allow it to waste.
113. A proper system having been adopted for
slaking the lime, it should not be opened to the air
until it is going to be spread over the land. When it
has been spread, it should be at once harrowed
into the soil, thus bringing it so into contact with
the soil, that it will exert its powers upon it, rather
than allow the quiet influence of the carbonic acid of
the atmosphere to rob the lime of its energy.
114. Another reason for adopting the use of the
harrow for covering in the lime, instead of using the
plough, is the well known tendency of lime to
sink in the soil. If it be mixed with the soil
near the surface, the ordinary tillage operations have
a tendency to keep it there; whereas, if the lime were
ploughed in, it would thereby commence its work at
a low level, and under many disadvantages.
115. Another point demands consideration in con-
nection with the use of lime, viz., whether the use of
lime renders a supply of some other manure
necessary. Many of the old maxims held by
farmers of experience, are found to have a foundation
of truth; but none more so than that which says —
. " The use of lime without manure,
i ' ; >'^ ' Will make the farm, and farmer poor."
There is much truth in this saying, and it will be well
to see the reason for it. One important action of
lime is bringing into a useful condition any organic
matter which is in the soil. It therefore uses up a
certain portion of the organic matter, and by its con-
tinued use, the organic matter of the soil would be
practically exhausted, unless fresh supplies of organic
matter were from time to time added to the soil.
Vnder a good system of husbandry, the ingr^v^se^
f
6o
AGRTCULTURR,
[CH.
produce of the land leads to an increase in the quan-
tity of manure, and this finds its way back to the land.
If, however, the lime be allowed to work out the
organic matter in the soil, and no proper return be
made to the land, then the land suffers very seriously.
Hence it may be taken as a rule, to which there are
very few exceptions, that the larger the quantity of
lime that is used, the more farm-yard manure should
also be supplied. The successful cultivation of the
land is throughout a well-balanced system, and any
departure from an ecpial-handed course of procedure
will soon show itself by the decreasing produce of
the land.
11 6. It was at one time the general practice for
lime and farm-yard manure to be used at or about
the same time.* The practice was, however, loudly
condemned in the early days of agricultural chemistry,
for it was shown that if lime were added to farm-yard
manure, its ammonia would be scattered into the
atmosphere, and it was thereby practically lost. Here
was an instance of the misapplication of a truth, from
overlooking the controlling influence consequent upon
this action taking place in the SOil. We have
already seen (107) that the action of caustic lime
upon a mixture of farm-yard manure and soil produces
a most valuable fertilizer, instead of causing a loss of
ammonia. To avoid all possibility of danger, these
manures should be added to the ^q\\ at different times.
The farm-yard manure should be ploughed into the
soil in the first instance, and the lime may then be
spread on the surface and harrowed into the land.
117. The land in many cases receives its supplies
of lime in a less powerful form, viz., in the various
forms of carbonate of lime. Chalk, marl, and
shell sand, are instances of this kind. The practice
of applying chalk to the land has very generally a
two-fold object in view, It adds to the land a supply
g( lime, ancl if it be freely applied it also filters the
vt.]
MARLS.
6t
general character of the soil to which it is added.
The lime thus added to the land is in the form of
carbonate ; it has none of the energy which distin-
guished the quick-lime. In some respects it is
capable of assisting the fertility of Ihe land as much
as the caustic lime ; but it requires more time to
accomplish its work. It neutralizes any organic acids
in the soil, it contributes a suppTy of lime as plant
food in a manner very similar to burnt lime, and it
exerts a powerful influence upon the mechanical
Condition of the soil, although in a somewhat different
manner.
ii8. Another large and valuable source of lime is
found in fc class of earths, known as marls. These
always contain some carbonate of lime ; but the quan-
tity varies greatly, some having about 6 or 8 per cent.,
whilst others contain So per cent, of carbonate of lime.
They differ also in the proportion of phosphate of
lime and of potash which they contain. The quantity
and composition of the silicates present also vary very
greatly. The value of a marl is therefore entirely
regulated by the fertilizing matter which it contains,
and the mechanical influence which it is capable of
exerting upon the soil to which it is applied. For a
long time these differences in the composition of marls
were not understood. Farmers found by the use of
marls, that one was better worth drawing ten miles
than another marl was worth drawing one mile, and
they persevered in their practice. When, however,
by the aid of chemistry the difference in their com-
position was shown, then the mystery was fully ex-
plained, and the evidence of practice fully justified.
119. The question is frequently asked. How am I
to know whether lime should be used as caustic lime,
or as carbonate of lime ? To determine this question
you must decide upon the result you wish to obtain.
If the land should be a sandy soil, with very little
organic matUr in it, and very weak powers of ve^e.*
table growth, you will conclude that this is not a case
for the use of caustic lime) because lime in that form
will exhaust the organic matter present, and there is
evidently none to spare. In such a case, it is there-
fore more than probable that its use in the form of
chalk or marl, will not only give the required supply
of lime, but it will give greater firmness and power to
the soil. Caustic lime would probably do more harm
than good, whilst in the milder form of chalk or marl
it would be highly beneficial.
1 20. As another illustrative case, we will take a
strong clay soil ; here it is more than probable that the
preference would be given to the use of caustic
lime, because of its more perfect action upoti the inor-
ganic matter. It is, however, quite possible that the
use of chalk might be less expensive, and although a
less desirable form of lime, it might be chosen for this
reason. Yet, even in sucli a case, it must be remem-
bered that the influence of the chalk upon the clay
Would have been very much increased if it had been
burnt. .:.:;,,■ , '.:'■ J'^^■:..
121. As a general rule, it may be taken that caustic
lime should not be used if there is a scarcity of vege-
table matter in the soil, and if it be light, and porous ;
but if there be a large quantity of organic matter, or if
the soil be heavy and tenacious, then lime ought to be
used in the caustic form. If you once understand the
special action of lime in the two conditions of caustic
and carbonate, you will have little difficulty in deter-
mining which is the moe desirable form. It must,
however, be remembered, that the varying circum-
stances and conditions of soil, climate, and the system
of husbandry, call for judgment and local experience.
For the present, at any rate, science must be, to a
great extent, limited to an explanation of successful
practice ; and when an apparent conflict arises be-
tween them, science must be content to indicate the
Uuth| without claiming for itself any certainty as to
tcH.
at a case
hat form
there is
is there-
form of
i supply
)ower to
>re harm
or marl
[ take a
that the
caustic
he inor-
that the
bough a
for this
remem-
the clay
ad been
caustic
)f vege-
3orous ;
er, or if
ht to be
and the
caustic
1 deter-
t must,
:ircum-
system
irience.
>e, to a
cessful
ses be-
ate the
y as to
VI.]
GPEBI^ MAPfVRES.
its accuracy. Many established local customs rep-
resented as theoretically erroneous, have been proved
to be correct by a more perfect knowledge of the
agencies which are in operation, and it is by no
means improbable that similar cases may yet come
under notice.
122. Green manures consist of crops grown for
the express purpose of being ploughed into the land
as manure. It is, in fact, manuring the land with
vegetable matter. As plants draw nourishment from
the atmosphere, the crop so grown for manure returns
to the soil more than it took from the soil, and so far
it enriches it. But whilst the leaves are thus accumu-
lating stores of fertility from the atmosphere, the roots
are actively searching for nourishment from the soil,
and storing this within them. Hence, when the crop
has been fully grown, a large quantity of plant food
has been gathered together, and this accumulation or
store of food is buried in the soil, ready for helping
the growth of the succeeding crop. This is no loss of
labor, for it is copying from the example of nature.
We have noticed (lo) that wh^n first the surface of
a rock has been broken into soil, some of the lower
forms of vegetation fix themselves there. These can
exist under greater difficulties than more highly organ-
ized varieties, and they act as pioneers, preparing the
way for higher and more useful varieties. They gather
from the atmosphere the elements of organic matter,
and having organized these bodies, the plant dies, and
leaves its organic matter in the new soil. The soil is
now prepared for a better variety of plant, and it, in its
turn, accumulates still larger supplies of organic mat-
ter. These havmg done their work, die, and so the
work of ennchmg the soil goes on. This is green
manuring, as true in character as any we can carry
out. :..iUU- ■ . ..:*.,^^■..
123. Rye, mustard, lupine, buckwheat,
veccheSi Italian rye-grasS| and clover are crops
m '
AGfiTCULTUJiR.
,\"\
[ctt.
which are employed as green manures; but the last
three are as a rule too tempting as food to be entirely
ploughed into the land, although a portion of such
crops is often left on the ground, for this purpose.
124. Green manures have a mechanical action
on the land, rendering it more open, aud therefore
better prepared for the roots of plants to penetratp^
and seek nourishment for the growing crop.
CHAPTER VII.
■:e'
1
li
TILLAGE opERATroNs. .: /,;:;:'
ia5. These tillage operations very greatly con-
tribute to the productiveness of rny soil. They
chiefly consist of ploughing, stirring, crushing,
and harrowing, and it will be seen that each of
these contributes to the required result by two distinct
means — -v ,.
By the greater freedom with which plants are ena*
bled to seek for and obtain their food; and r
By increasing the plant food in the soil. ; !
The operation of ploughing brings up from beneath
the surface, soil which has been buried, and thereby
exposes fresh material to the atmosphere. Ploughing
is usually limited to a turning over of the soil
which has been previously under cultivation. When
the subsoil is ploughed, it is distinguished as subsoil
ploughing, but this is generally stirred and not
brought up to th€ surface, because it frequently has
harsh and acrid matter present. As a rule, very great
caution is necessary in bringing up to the surface any
of the subsoil, especially when it is at all of a sour
nature. There must be some good reasons for these
practices, and it will be well to search thetn out.
(26. the first effect of ploughing is to give th|^
mm
VII.]
A CT/ON' OF DO UBLE SILICA TES.
6i
land a greater looseness and friability of character.
Land gets a certain amount of firmness during the
growth and removal of any crop, ani^ it is for this
reason necessary that the land should be broken up.
Ploughing also becomes a preparation for other work,
which breaks it up still more completely. If land has
become hard and firm, it is not in a favorable con-
dition for the roots of plants to penetrate and search
for food. If, by the mechanical condition of the soil,
the plant is prevented from exercising a freedom of
growth, the yield from the crop must be thereby
diminished.
127. Not less important than this is the increase in
the fertility of a soil caused by its exposure to the
sun and air. The soil upon the surface having had
the benefit of this action, is in a good condition for
being turned down, and the under-soil will be fresh-
ened by exposure. The soil becomes " freshened" as
it is often termed, or refreshed by the oxidation of its
particles, which have in many cases been reduced to
a lower condition of oxidation during the time it has
been covered up. The oxides of iron are examples
of this action; when they are exposed near the surface
to the sun and air, they become fully charged with
oxygen, but when buried in the soil they give up some
portion of their oxygen in the several decompositions
which take place in the soil, and thereby they become
again reduced to a lower form of oxide. Still they are
hereby performing a most important duty, as they
really become "carriers of oxygen," and in some
cases convey ammonia also.
128. A still more important source of fertility is
obtained by bringing the double silicates of the
soil (24) into contact with the atmospheric
air. These have the power of absorbing am-
monia from the atmosphere. We have already
explained (104) how strong is the preference shown
for the formation of double silicates containing am-
AGRICULTURE.
[CH.
M
f>
kl
monia, and if any other double silicate exists in the
soil naturally, or hCv been produced there by any
artificial means, such double silicate will, by exposure
to the air, take in from the atmosphere a valuable
store of ammonia ready for the next crop.
129. The exposure of the soil by ploughing also
enables it to derive full advantage from the frostS
and rains of winter. We have in this way a break-
ing up of the soil going on through many months,
and much of the dormant matter of the soil is thus
rendered active, and available for vegetation.
130. That which is accomplished by the plough is
also favoured and promoted by those lesser operations,
which assist in bringing the earth into a finer condition
for the growth of a crop. There are times when
Stirring^ is preferable to the ploughing of the land.
When land has been ploughed up before winter, and
exposed to the winter's frosts, it is often better to keep
the fine earth thus obtained upon the surface, rather
than bury it. The use of a stirrer, whilst it moves the
land, and gives it the looseness desired for the roots,
does not bury the finely-broken earth which is on the
surface, and which is most valuable as a seed-bed for
the next crop.
131. When the surface of the land is not sufficiently
fine for a seed-bed, then we find the crushing of the
roller, and the gentle stirring of the harrow,
assist in breaking the lumps on the surface into a finer
condition. The fineness of the soil is a most
important point, when required as a seed-bed in which
seeds can make a successful growth. In a rough soil
a small seed will fall from one lump to another, until
it has got too deep in the soil to make proper growth,
and it therefore becomes necessary, by the use of
rollers, to crush the rough lumps in the soil to pre-
vent waste of seed.
132. A fine condition of earth is also necessary
for a seed-bed in order that the early growth may
\'^\■^\
MMiiii
[CH.
VII.]
DRAINAGE OF THE LAND,
67
Ists in the
re by any
|r exposure
a valuable
jhing also
he fro£ts
y a break-
y months,
yX is thus
on.
plough is
perations,
condition
mes when
the land,
'inter, and
:er to keep
Lce, rather
jKioves the
the roots,
I is on the
ed-bed for
ufficiently
igof the
harrow,
ito a finer
!s a most
d in which
rough soil
ther, until
r growth,
le use of
il to pre-
necessary
07th may
be encouraged. For a certain time the seed supplies
to the young plant which is being developed from if,
all the nourishment the young plant requires, but the
little rootlets will soon have to take upon themselves
the duty of obtaining food from th.e soil, and unless
the fineness of the soil admits; of a close approach of
these rootlets, they fail to establish the young plants
firmly in the ground. Two distinct conditions are
necessary for plant growth. A fineness of the
soil such as has been described, and also a moderate
firmness, whereby the plant is fixed in the land.
Both of these conditions are secured by a judicious
use of the roller.
133. In thesucceediVig stages of the plant's growth,
various mechanical operations,such as horse-hoeing^
or hoeing by hand labour, are carried on with the
object of maintaining the /arid in a free and open
condition, so that air and moisture can enter, and the
roots spread through the soil with freedom in their
search for food. The same operations are also useful
for the destruction pf weeds, which would other-
wise take the food intended for the cultivated, plant,
and occupy space which is most desirable for assisting
a. luxuriant growth of the crop.
134. Few operations carried out by the farmer,
exercise a more decided influence upon other branches
of work, than the drainage of the land. This
drainage is carried out, by making in tht: land channels
and water courses, which enable the water to escapa
from its imprisonment in the soil. So long as an
excess of water is kept in the soil, every form of labor
upon the land is rendered more difficult, and the
growth of the crop is very much slower and less per-
fect than it otherwise would be.
135. As soon as these water courses or drains have
been made, the water commences running into them,
and the land thereby becomes relieved of the excess
which previously existed there. As the water drains
'■ik.. -
.'•^
68
AGRICULTURE,
[cH.
f
(<
away from the soil, so air is drawn into the soil to
tak< itc place; otherwise the water could not escape
from ihe ,'?,nd. If you nearly fill a bucket with stones,
and pour water so as to cover them, the air has no
opportunity of gaining access to these stones; but if
you make an opening in the bottom of the bucket, the
water runs out, and as the surface of the water lowers
so the air follows, and gains access to the stones.
This simple illustration will show how it is that the
construction of drains for carrying away the water, of
necessity brin£;s the atmospheric air into the soil.
136. As soon as the air is admitted to a ntwly
drained soil, a great change takes place. The un-
healthy decomposition which had been going on in
the stagnant water, had caused an accumulation of
organic acids which made the soil unsuitable for the
growth of any of our cultivated crops. The entrance
of the air, bringing with it the pure oxygen of the
atmosphere, soon converts these organic acids into
more useful forms. It also enables an action to be
commenced upon the Inorganic matter present,
whereby some of its dormant elements are rendered
active and useful for plant growth. Thus the first
good result of drainage is to remove from the land the
stagnant water it contained, and draw in tlxe purifying
atmospheric air to increase the fertility of the land.
137. The drainage of land also gives an outlet from
the soil for any soluble matter which is injurious to
vegetation. The passage of water through the soil
gradually dissolves this out, and practically washes it
from the land.
138. A very marked difference is observable
in the temperature, or warmth of drained, and
undrainea lands. You are no doubt aware that
evaporation necessitates the employment of heat.
If a vessel of water be placed upon a fire the heat
it receives first causes the water to boil. If the heat
be continued the water does not get any hotter, but
«<pi
VII ]
COLD SOILS.
^
the heat is now entirely used in converting water
into steam, or evaporating it. Water which has to be
evaporated from the soil, requires heat to accomplish
the work, just as if that water were boiled away in a
vessel, upon a fire of coal.
139. It has been calculated, that the water which
has to be evaporated from an acre of undrained land
in the course of a year, may be taken as equal to the
work of from 200 to 300 tons of coal The sun's
rays which fall upon such land do not warm undrained
land, and thereby encourage vegetation, for they have
in the first place to dry the land. Every warm
breeze which passes over it, instead of favoring plant
life, is chilled by the evaporation of water. In fact
the heat which ought to be used for stimulating the
growing crop, is very largely employed in drying the
land. Such lands are consequently recognized as
**cold."
140. Drained land is warmer than undrained land
for another reason. It is well known that, generally
speaking, warm water is lighter than cold water, and
will rise to the top of any vessel in which it is con-
tained. Suppose a warm breeze passes over land
containing stagnant water, the heat which is not
employed in evaporating the water will warm it
slightly, but the-water thus warmed will remain at ths
top, and the heat will not be communicated to th*
soil beneath. Oa the other hand, suppose a coli
breeze to pass over the undrained land, this will chill
the water at the top, but the water thus cooled will
immediately sink into the soil, and be replaced by the
warmer water from beneath. Thus it robs the soil of
a part of its heat. In land in which a proper circula-
tion of water is secured, the warm rain, instead of
remaining at the top and losing its heat uselessly,
penetrates through the soil, and warms it. The influ-
ence of this jncrease of temperature upon the product-
iveness of the land is very striking, 'ihe harvest
to
AGRICULTURE.
[CH.
comes several weeks earlier than it otherwise would,
and corn of good character is grown where the land
previously produced only a very inferior quality.
141. The next great advantage is the more per-
fect use of any manure which may be added to
the soil. The healthy condition of the soil renders
the use of lime, farm-yard dung, and artificial manures
much more beneficial. If the land is too wet, these
manures are to a great extent wasted, because there is
no vigorous growth to utilize them, and their decom-
position is of an unsatisfactory character. Until land
has had good and proper drainage, it is almost useless
to attempt its improvement by the use of manure. It
would be better to use the manure upon land fit to
receive it. . • - i^. "voi .
142. The same circumstances which make land
more healthy for vegetable growth, also make it
more healthy for animal life. This is largely
due to the fact that a superior quality of herbag«
maintains stock more perfectly, and gives them a
greater vigour of life, which is in itself a great protec-
tion agamst disease. An insufficient supply of proper
food, greatly predisposes an animal for disease. Hence,
just in proportion as land produces inferior food, de-
ficient in nourishment, so the stock upon that land
becomes unhealthy, and more liable to disease. In
addition to this, the damp character of the land exerts
a direct influence upon the animals kept upon it, pro-
ducing various forms of disease.
143. The dramage of land reduces the COSt of
all the tillage operations, enables the land to be
cultivated with much less labor, and it extends the
time during which the work may be done.
[CH.
mse would,
re the land
quality.
nore per-
J added to
oil renders
al manures
wet, these
ise there is
eir decom-
Until land
lost useless
anure. It
land fit to
nake land
• make it
is largely
>f herbags
;s them a
;at protec-
of proper
>e. Hence,
food, de-
that land
ease. In
nd exerts
)n it, pro-
cost of
md to be
ends the
vni.]
J?0 TA TION OF CROPS.
71
CHAPTER VIII.
ROTATION OF CROPS.
144. The practice of agriculture has long proved
the importance of regulating in proper order, the suc-
cession in which crops should be grown. It has been
found that if some of our crops be grown upon the
same land year after year, difficulties have to be over-
come, for the crop to be kept in a healthy and lux-
uriant condition. It is commonly remarked by far-
mers that the land is " sick" of a crop, and clover
is especially referred to in this way. If a field is
"clover sick," it is unwise to sow clover again
until the land has become ready Cor it. The same
influence has been noticed in connection with other
crops; this has led to the crops being changed fre-
quently, and experience has taught us much, as to the
manner in which we may best make these changes.
145. The rotation of crops adopted in different
districts, represents the experience derived by farmers
as to the best order in which our crops should follow
each other. The term " rotation of crops" may
therefore be taken to mean, the order of succession in
which our crops are grown. This is an exceedingly
important matter, for it exercises great influence upon
the success of farm operations, and it is therefore
desirable that the conditions which influence these
results should be clearly understood.
146. At one time it was thought that De Candolle
was correct, in his explanation of the cause of land
becoming " sick" of a crop. He had observed that
when the same crops had been grown repeatedly in
direct succession on the same land, they became
unhealthy; that there was a want of vigour, and the
produce became small. If, however, another kind of
crop were sown, it seemed to thrive luxuriantly, where
AGRlCUlTUI^n,
Tcff.
ill
»
the other pined away. He explained this by assum-
ing that plants threw off excrcmentitious matter in the
soil, which after a time became so very objectionable
to the crop, that it became unhealthy and died. The
excrement of one crop he considered lo be even
desirable for another crop; at any rate it was supposed
to be unobjectionable. He based his explanation
upon the assumption that plants treated the food they
received somewhat in the same way as animals did,
viz., that after making use of such portions of the
food as were desirable, the residue was thrown off as
an excrement. De Candolle's theory has, however,
been generally set aside, as less satisfactory tlian that
advanced by Liebig.
147. According to Liebig's views, the difficulty
arose from a want of proper food for the plant,
and he held that the plant became unhealthy and
pined away, simply because the plant needed food
which the soil could not supply. He supported this
by showing the number of different substances which
our cultivated crops required the soil to supply (41).
He showed that when a soil was nearly exhausted of
the materials which one crop required, it might still
contain an abundant supply of food for another kind
of crop. He was of opinion that whilst one crop
would have had a short supply of food, there was an
abundance in the soil for the other crop. The one
crop might therefore fail, whilst the other would
flourish. It has been generally accepted as one of the
rules which should regulate the rotation of crops, that
those plants which required the same kind
of food, should be kept as far apart as
possible, whilst those which require different sup-
plies might follow each other.
148. The second rule is that plants of the
same habit of o^rowth, and general character
should not follow each other. For instance,
gome plants strike deeply into the soil, and obtain
VI
m
vni]
NORFOLK ROTATION,
73
much of their food from the lower portions of the
soil, whereas other plants send out their roots amongst
the surface soil and are shallow rooted. Thus the
clover roots strike deeply into the soil, and really
enrich the upper soil, by adding to it matter d-awn
from beneath it. Wheat is found to grow luxuriantly
upon land in which the clover has flourished. A good
clover ley is a tolerably sure promise for a fine crop
of wheat. This probably arises from two causes,
which readily explain this well known fact. The
clover has not drawn from the upper soil the food
which the wheat requires, but has stored up in its
closely matted roots, a large quantity of nitrogenous
matter on which the wheat plant can feed. The roots
of the wheat also find in the clover ley, freedom for
their growth, amidst the supplies on which it has to
rely for nourishment.
149. Another illustration of the conditions which
influence the rotation of crops is shown in the case
of beans following wheat; and the table already given
(41) shows the substances drawn by each of these
crops. Wheat requires a large supply of silicates,
beans take one-tenth of the quantity; on the other hand
wheat requires only about one-half the potash and
phosphoric acid that the bean crop needs. So also
amongst the white straw corn crops there is another
difference observable, for whilst wheat roots deeply,
barley roots shallow; and these crops therefore draw
their supplies from two different layers in the soil.
150. The Norfolk rotation, or the four years*
course of cropping, is a good representative system,
and one which has probably been more largely, and
more generally adopted than any other. It consisted
of the following course of crops: —
*~f j^'
1st Year, Turnips, or other Root Crop,
2nd ,, Barley.
3rd „ Clo'»er.
4th „ Wheat.
94
AGRICULTURE.
[cH
;; I
The advantages of this course were as follows: — The
turnip crop gave great facilities for thoroughly cleaning
the land; it was also a convenient time for the use
of manure, and the root crop flourished under these
circumstances. The land was thus prepared for
barley, and for the clover seed sown amongst it, for
it was clean and in good condition. A strong
growth of clover was tolerably sure to check the
growth of weeds, and when the clover ley was broken
up for wheat, the land was in fine condition for its
growth. Thus every crop was exerting a favourable
influence upon that which had to follow.
151. After a few years it became necessary in many
cases to alter the system. Some farmers whose land
was not as good as other soils, or who did not add
fertilizing matter as liberally as other farmers, found
that their crops were falling off in their yield, and that
they must have corn less frequently. In such cases
the clover was allowed to remain a second year, and
this made it a five years' course. Thus —
1st Year, Turnips, or other Root Crop.
2nd ,, Barley.
3rd ,, Clover.
4th ,, Do.
5th ,, Wheat.
152. But, while some farmers had to have corn less
frequently, others found the land becoming so much
more fertile, that they were obliged to grow more corn
from it. The barley crop was found to grow so strong
and coarse, that it lost quality. Farmers therefore
sowed wheat after the turnips, and this crop made good
use of the abundant supply of fertilizing matter in the
soil. The barley was sown after the wheat crop, and
grew more steadily, and yielded a higher quality of
corn. This gave a second form of five years'
rotation, in which more corn was grown in conse-
quence of the high cultivation of the land. This ro-
tation was—
>r ^ *wi( H Hiy wL «i m i ui ! "" ' w w ' i
[CH
s:— The
cleaning
the use
er these
ired for
St it, for
^ strong
eck the
5 broken
n for its
curable
in many
)se land
not add
;, found
ind that
:h cases
ar, and
VIII.] CONTINUOUS GROWTH OF CORN.
75
)rn less
5 much
re corn
strong
erefore
le good
r in the
>p, and
ility of
rears'
conse-
his ro«
1st Year, Turnips, or other Root Crop,
and ,, Wheat.
3rd ,, Barley.
4th ,, Clover.
5th „ Wheat.
153. It would be impossible to describe here, all the
various rotations which are in use, but these are taken
as representative cases, showing, in the first place, a
course of cropping founded on sound principles, and
afterwards altered for equally good reasons, so that
the growth of corn should in the one case be less fre-
quent, and in the other instance more frequent.
154. In some cases we find what must be called
a bad rotation, for instance —
■ ' M. , / ( 1st Year, Oats.
1 ., V 2nd ,, Do.
^ ^ 3rd ,, Wheat.
4th and following years, Clover or Grass Seeds.
Here we have all the conditions of a good rotation
(150) set aside. The land did not have proper culti-
vation for rendering it free from weeds. The applica-
tion of manure would, under such management, be
excessively small, even if any were used, and the re-
peated growth of corn without proper cultivation and
manure, is alike to the injury of the land and the far-
mer. The land when laid down in clover or grass seed
would be as foul as it well could be, instead of being
so clean that the clover could fully occupy the ground,
and yield a rich and nutritious crop.
155. The rotation adopted upon a farm must also be
regulated so as to secure an equal distribution of
the work throughout the year, and to give that
variety of food and litter which the system of
farming renders necessary.
156. The success which has attended the continu-
ous growth of corn appears, at first sight, to be in
direct opposition to the theory of the rotation of crops
we have referred to. It has been most satisfactorily
'4(
i
f
76
AGRICULTURE,
[CH.
I.
shown that, under certain circumstances, corn can be
successfully and profitably grown upon land, year after
year, for a long period of time. This, however, admits
of a ready explanation. If you refer to the quantities
of inorganic matter removed from the soil (41) you
will see that wheat makes a large demand upon the
soil for silica ; but when you compare the quantities of
phosphoric acid, lime, potash, and soda removed by
the several crops, you will observe very great differ-
ences between that which is necessary for the wheat
crop, and that required for the other crops there re-
ferred to. For instance, a crop of beans takes nearly
double the phosphoric acid required for wheat, and a
turnip crop takes three times the quantity. A crop of
beans takes more than three times as much lime as a
crop of wheat, and a crop of turnips and clover each
takes ten times as much. So also with potash, beans
taking four times the quantity required by wheat,
turnips taking eight times as much, while clover takes
double the quantity ; and so also in the case of soda.
Without laying too much stress upon the exact pro-
portions so drawn from the land, it is evident that,
whilst wheat makes a larger demand upon the soil
for silica, comparatively speaking, it requires but a
moderate supply of other inorganic fertilizers. '
157. In fact, the continuous growth of wheat with-
draws from the land a constituent which occurs prac-
tically in an unlimited quantity. But it must be
remembered, that the successful conduct of this practice
necessitates that thorough cultivation of the soil,
which makes a large quantity of the silica existing in it
in a dormant condition take an active form, and there-
by become available for the growth of the crop. A
supply of silica cannot thus be made available from
all soils, as for instance in the case of sandy soils,
although the silica exists in these in a very large
proportion. The soils upon which this result is obtain-
able, are those which contain a large supply of silica in
-T=i,,a«5««!4*aKtl«l*-«
[CH.
VIII.]
TREA TMENT OF LIVE STOCK.
11
the form of clay, or silicate of alumina — and especially
those in which the double silicates are found. It is,
however, necessary, in ahnost every soil, to supplement
the good influence of thorough cultivation, by
the judicious use of manure.
CHAPTER IX.
'■ LIVE STOCK.
158. The system of farming adopted must deter-
mine the kind of stock which is kept upon the farm.
In some cases, dairy cows and pigs will be the live
stock kept, in other cases, sheep, and some farms will
have cattle; others, again, will adopt a mixed hus-
bandry, and have some of each variety. Without, at
the present time, going into detail on the relative ad-
vantages of each, it may be sufficient to remark, that
whatever may be the kind of stock kept, it should
be of good quality, and suited to the district.
159. Upon the good management of the live stock
of the farm, much of the farmer's success depends;
and it is satisfactory to know that that which promotes
the comfort of the stock, also increases the profit they
produce. Harsh and cruel treatment should be recog-
nized as decreasing the profit which any animal will
produce, because it is punishing to the stock. The
suffering undergone by an animal, involves a corre-
sponding loss to the owner. If no higher motive
than profit exists for careful and kind treatment, this
ought to be enough; but it cannot be too much im-
pressed upon all having the care of live stocky that
some better motive should guide them.
"A merciful man unto his beast is kind,
But brutal actions show a brutal mind."
Kind and careful treatment of stock, is one of the
78
AGRICULTURE.
[CH.
i
foundation stones of good and profitable manage-
ment.
1 60. The supply of food should be regular, and of
such a character as to keep stock steadily improving.
Some few years since, it was very common for the
stock kept through the winter months to lose nearly all
the flesh they had gained in the preceding summer,
simply because sufficient food was not suppl'Vd to
prevent this waste of the body. It is now known to
be not only cruel, but unprofitable, and such
bad management is, in consequence, rarely seen at
the present day.
161. Improvements have been made in live
stock, whereby they have become more economical
producers of meat. A certain quantity of food eaten
by some of our " improved breeds," will produce more
meat than if it were eaten by one of the original
unimproved stock. The remark applies to cattle,
sheep, and pigs, for in each similaf modifications
have been produced, although differing in degree.
162. Before the great changes, which we call "im-
provements," were stamped upon the various breeds of
stock, there were many points of character in which
they agreed. They were generally very active in their
habits, able to travel great distances without much
trouble, wild and restless in their disposition, fond of
liberty, hardy in their constitution, and were able to
give abundance of milk to their offspring.
163. In our 'improved breeds" this has been
greatly alte'^ed. The activity of the body hr'.s been
diminished, and the animals have become indisposed
to much exercise. Instead of ranging over wide tracts
of country for their food, they look for its supply
without having to take much labour to secure it.
They rejoice in quiet and peaceful lives, with abun-
dance of food, and the least possible amount of
trouble. They are tender and delicate, they breed with
great difficulty,. and have a very small supply of milk
LCH.
nanage-
•, and of
proving.
for the
learly all
summer,
phVd to
novvn to
nd such
seen at
in live
gnomical
od eaten
iice more
original
o cattle,
ifications
egree.
:all "im-
breedsof
in which
e in their
lUt much
I, fond of
e able to
has been
hr.s been
[disposed
de tracts
s supply
ecure it.
!th abun-
nount of
reed with
/ of milk
IX.]
TMPRO VED BREEDS OF STOCK.
79
for theiroffspring This is the change which has been
accomplished in our " improved breeds" of stock, and
many will be disposea to inquire, wherein does
the improvement consist?
164. The actual improvement c6nsists, in a greater
economy in the production of meat from vege-
table food. If a certain quantity of corn, or roots, or
clover had to be converted into meat,with the least pos-
sible loss of time and material, then we should succeed
best, if we made use of an animal of an improved breed,
to do the work. Here we should find the animal
quietly and placidly taking its food, and then resting
whilst that food was undergoing the changes necessary
to convert it into the flesh of that animal. As soon
as this had proceeded for a certain time, fresh food
would be supplied,and the work of growth encouraged;
finally, when it was thought desirable to complete the
fattening of the animal, suitable food would be given,
and thus we should be able to produce early maturity,
and thereby obtain meat in its cheapest form. In
other words, we have made our several breeds of farm
stock into excellent machines for the production of
meat. In doing so we have deprived them of much
of that energy of life, and hardy character, with which
they were prepared to withstand the difficulties and
the dangers of a life, in which they had to take care of
themselves, far more than they were taken care of.
165. Thus we are able to control the character, and
the form of our domesticated animals, and produce
very extraordinary variations from the original type.
This success is not attained by sudden changes, but
by taking advantages of favourable peculiarities, en-
couraging their development, and then rendering them
more permanent. It must, however, be remembered,
that we can only control the peculiarities of animal
life, by such methods as the laws of animal life permit.
In this way we have obtained improved breeds of
cattle, sheep, and pigs altogether different in shape, in
8o
AGRICULTURE.
[CH.
; I
\\
W
I
I
their habits of life,and in their constitutional character,
from the origin al breeds from which they were obtained.
These variations must, however, be regarded as unna-
tural and abnormal conditions, and as being obtained
for the more economical production of meat. We
cannot run contrary to the course of nature, yet, like
mariners who have adverse winds to deal with, we can
" tack about," so as to be carried forward by the
functions of animal life, to the attainment of a result
totally different from that which the same agencies
would have produced, had the animal existed in a
wild condition.
1 66. Fat is produced from the non-tiitrogenous
portions of the animal's food, and its chief use in the
animal body is to maintain the heat of the body.
The temperature of the animal body is higher than
the air in which it usually lives. An ox has a body-
heat of ioo° Fahr., and for its healthy condition this
temperature should be maintained. If there were no
internal source of heat, the warmth of the body would
fall to that of the surrounding air, and this does take
placed after death. The lungs of the animal assist
largely in this very important duty. The oxygen of
the atmDsphere being drawn into the lungs, is thus
enabled to act upon the non-nitrogenous matters
which are in the blood. These matters contain a
large quantity of carbon, and by the union of the
oxygen of the air with the carbon of the food, we
have carbonic acid formed. The animal therefore
draws in oxygen and throws off carbonic acid. The
lungs thereby do the work of a pair of bellows, and by
the addition of oxygen to the blood the carbon is grad-
ually burnt off or oxidized, as the blood is circulating
through the body of the animal. The following analysis
of atmospheric air and the breath of an animal, given
by Playfair, will sufficiently illustrate this fact: —
[CH.
:haracter,
obtained.
as unna-
obtained
eat. We
, yet, like
h, we can
d by the
•f a result
agencies
sted in a
)genous
use in the
le body.
jher than
a body-
iition this
i were no
•dy would
does take
lal assist
>xygen of
s, is thus
; matters
:ontain a
ti of the
food, we
therefore
id. The
s, and by
1 is grad-
rculating
J analysis
lal, given
ict: —
IX.]
ACTION OF THE LUNGS.
dt
.'!'-' ' ' '
Nitrogen, ,
Oxygen, . .
Carbonic acid, .
Composition of
Atmospheric Air drawn
into the Lungs.
Composition of
the Ureath thrown oft
froni tlic Lungs.
79-16 .
20-80
•04
79'l6
16-84
4-00
TOO 00 100-00
This shows a very small quantity of carbonic acid in
the atmospheric air, and how greai"ly the carbonic
acid is increased by a single respiration of the animal.
We have therefore, by the healthy action of the lungs
upon blood properly supplied with non-nitrogenous
matter, an internal source of heat which maintains the
warmth of the body, up to a healthy standard.
167. Two conditions are essentially necessary to
secure this result —
The lungs must be sufficiently powerful, and,
The blood must contain sufficient heat-producing
matter.
The demands made for the maintenance of the
warmth of the body, are entirely regulated by the loss
of heat from the body. If the loss of lieat be great,
the demand for heat is great also; and if the loss of
heat be small, there is only a small supply needed.
If the air should be very cold, there will be a great
'loss of warmth, and the demand for internal heat will
be great; but if, by sheltering the animal from the
cold air, the loss of heat is reduced, then the demand
for internal heat will be decreased also. It is there-
fore quite within our power to reduce the loss of heat
from, the body, and thereby to economize the
fuel or heat-producing matter of the food.
168. The demands made upon the lungs and the
food, arc therefore entirely regulated by tlie waste of
wariiitii trom the body. If there be plenty of heat-*
i
producing matter in the blood, the lungs work away
at it, and purify the blood just to that degree which is
necessary for keeping up the warmth of the body.
Shelter from the cold is therefore desirable upon
economical grounds, for thereby less of the heat-pro-
ducing matter in the blood is thus used, and that
wnich remains can be stored up in the animal as
fat.
169. The formation of fat is also encouraged by
the motion of the body being limited, for as
motion stimulates the lungs to greater activity, so a
larger proportion of the heat-producing matter is
burnt off, and less remains to be converted into fat.
170. The size of the lung influences the forma-
tion of fat, for the quantity of oxygen drawn into the
lungs, and dissolved in the blood is regulated thereby.
A largely developed lung will more lully oxidize
the heat-producing matter of the blood than a
small lung, and hence it has been found that the
animals which fatten most readily have the smallest
lungs.
171. It has also been observed that a small Of
inactive liver promotes fattening, but there are
limits which cannot be passed without fatal conse-
quences. Sheep which have the rot in the liver, fatten
with greater rapidity during the first eight or ten
weeks after they have taken it, than previously, but
aftei' this length of time the I'ver becomes so rotten,
that the general health suffers, and the animal pines
away and dies.
172. The management carried out for establishing
our improved breeds, encourages the formation of
small lungs and small livers. By prevent' M.g the
animals taking much exercise, these organs also
become slow in their action and naturally sluggish.
A larger proportion of the heat-producing matter is left,
and becomes stored up in the animal as fat. We there*
{or9 consider such animals good fattening animalS|
^™4i
IX.]
CONSTITVTtonAt STRENGTH.
■is
because we get a larger quantity of fat formed from a
given quantity of food.
173. It is necessary now to look at the other side
of the picture. Such animals are delicate, and require
more care and protection than others. We have
given these animals small lungs, and sluggish livers,
and consequently the power of the animal to maintain
its warmth is reduced. If such animals are exposed
to cold weather, we soon find that they have reduced
powers for maintaining their warmth, the healthy
condition of the body suffers, and the animal becomes
subject to disease. The conditions which render
animals energetic, active, and hardy, have in these
cases been modified to make them good producers
of fat, and in proportion as we have succeeded in this
attempt, so we have produced a weak and delicate
constitution.
174. These circumstances fully account for what
is known as a loss of constitutional strength.
If you seek for this, you find it where the laws of
animal life exercise their full influence. The wild,
undomesticated animal, possesses a healthy and vigor-
ous system, and every part of his body possesses a
thoroughly healthy character, and thus the full energy
of constitutional strength is maintained. Nature rebels
against our " improvements" in the several breeds of
stock, and just in proportion as we are successful in
producing unnatural specimens so we find the laws
of animal life coming in to check us in keeping up
the succession.
175. Shelter and economy of food, should never be
carried out at a sacrifice of the proper ventilation
of buildings. It has been shown that animals draw
into the lungs atmospheric air, use a portion of the
oxygen, and throw off carbonic acid. This carbonic
acid is a very dangerous gas, for no animal can live
in it, and it should therefore be carried off from the
building. An instance showing the deadly character oC
B4
AGRICULTURE.
«<w*
[Ctt.
this carbonic acid, occurred a few years since on board
a vessel which was bringing sheep from Holland to
England. In consequence of stormy weather, the
sheep were placed below deck, and the hatches closed
so that they could get no fresh air. When the hatches
were opened it was found that the sheep were dead,
and they had to be thrown overboard. They had
been poisoned, by breathing the carbonic acid
thrown off from their lungs, instead of breathing pure
air.
176. Although the action of the carbonic acid is
seldom imiu'^diately fatal, we still fmi considerable
injury arising from its being allowed to remain in the
building. This injury is very much more serious than
it otherwise would be, because the ill effects are not
so easily traced to the proper cause. If the carbonic
acid cannot get away, fresh air cannot obtain entrance,
and it is only a question of how long the animal can
exist. If there be no supply of fresh air the animal
must die. It is very seldom, however, that the
evil influence continues long enough to be fatal, but
we very frequently find such a deficient supply of
fresh air, that the carbon of the food cannot be burnt
off by the lungs, consequently accumulations take place
on the lungs and these become diseased. When-
ever we fully understand the wideextentof loss which
arises from the buildings in which cattle are kept, not
being properly ventilated, we shall be astonished at its
magnitude. The prevalence of diseased lungs in farm
stock arising from a want of proper ventilation, is in-
creasing year by year, and as yet the cause is but
imperfectly recognized. If the carbonic acid be once
looked upon in its true light in relation to animal life,
as a poisonous gas, there will be a greater willing-
ness to adopt measures for assisting its departure
from buildings in which live stock are kept, and for
securing for them a free supply of pure air.
[Ctt.
J on board
olland to
ather, the
les closed
le hatches
ere dead,
They had
onic acid
thing pure
ic acid is
nsiderable
ain in the
irious than
:ts are not
e carbonic
n entrance,
inimal can
the animal
■, that the
2 fatal, but
supply of
ot be burnt
s take place
d. When-
: loss which
e kept, not
lished at its
ngsin farm
ation, is in-
Luse is but
:idbe once
inimal life,
ter willing-
1 departure
)t, and for
lir.
X.]
COMPOSITION OF FOOD.
83
CHAPTER X.
FOOD OF FARM STOCK.
177. The food of farm stock comprises numerous
substances, which differ very widely in their character
and composition. The extent to which cultivation,
soil, climate, and manure aflect the nutritive value of
our crops, is a subject of the dL'c}.est importance for
the consideration of farmers, and it may be hoped
that, as the principles regulating vegetable growth
become more generally known, we shall be able to
increase the value of the food employed. We have
already (32) referred to the several substances which
we find in vegetable matter, and shown that they
are divided into two groups — nitrogenous and non-
nitrogenous.
178. The non-nitrogenous bodies — starch, gum,
sugar, and oil — have two distinct duties.
The maintenance of the warmth of the body, and
The production of fat.
It is from the food, that the blood obtains its supply
of the materials, by which the warmth of the body is
kept up by the respiration of the lungs. It is more than
probable that when starch, gum, and sugar are present
in the food, these are first acted upon for the produc-
tion of animal heat, but if these substances are absent,
then the oily matter of food has to perform tliis ser-
vice. These bodies may therefore be regarded as the
heat-producing matters in food.
179. The nitrogenous substances in food — albu-
men, casein, and fibrin — have two other perfectly
distinct duties to perform. They have
To repair the waste of the body, and
To develape muscular growth.
M
AGRICULTURE.
[CH.
The first duty draws our attention to the waste of the
body, which is constantly going on. Every movement
of the body causes a waste of the part exercised. If
the strain or effort be violent, the waste of tissue is
greater than if the movement be gentle. The waste
is, however, quickly repaired, and, as if to prepare
that part of the body for future demands, it is actually
strengthened. Hence, although exercise causes a
waste of the tissues, it tends to increase the strength
of the part exercised. All are familiar with the well-
known strength of the blacksmith's arm, resulting, as
it does, from severe exercise; and in contrast with
this we have the weak and feeble arm, which has been
kept from exercise. The waste of the body makes its
demand upon the several substances of this nitro-
genous group, and this is the first duty they have to
perform. Any surplus which remains is available for
muscular growth. This group therefore represents the
flesh-forming matter of food.
1 80. There is another class of bodies present in
food, and these are known as the mineral matter of
food. Their chief duty is to supply materials for the
growth of the skeleton.
181. The various articles of food which we employ
for feeding farm stock generally contain a mixture of
different bodies, belonging to two, and sometimes to
three of these groups. Our judgment upon the action
of food, is therefore influenced by what we know of its
composition. If, for instance, there should be none
of the flesh-forming bodies — the nitrogenous group —
present, then it would be impossible for flesh to be
formed. We are not justified, however, in saying that
it none of the heat-producing matters — the non-nitro-
genous group — are present, that it would be impos-
sible to maintain the warmth of the body. There is
feason to believe that the nitrogenous group, which
contains (in addition to nitrogen) carbon, hydrogen,
ftnd oxygen, the elements of which the heat-producing
*Ml4
[CH.
ste of the
lovement
:ised. If
tissue is
'he waste
prepare
s actually
causes a
strength
the well-
ulting, as
trust with
has been
makes its
lis nitro-
y have to
lilable for
esents the
•resent in
matter of
lis for the
'e employ
(lixture of
letimes to
the action
now of its
I be none
s group —
esh to be
lying that
lon-nitro-
)e impos-
There is
jp, which
lydrogen,
)roducing
X.]
DIGESTION OF FOOD,
group are constituted, can, on an emergency, contrib-
ute matter for the maintenance of warmth. It is not,
however, their legitimate duty, and when it is per-
formed by them it is done at a sacrifice of economy.
182. Before we proceed to notice the economical
use of food it will be desirable to outline in a verv
brief manner, the very important changes whicn
food has to undergo, before it can be utilized for
the purpose of animal life. For this purpose we will
take cattle as the basis of our comments. A bullock
has four stomachs, of which the first, which is known
as the rumen, is the largest of the scries; it is simply
used for receiving the fresh gathered food. Whilst
the food remains in this stomach, it receives moisture
from the saliva, which is passed down the gullet from
the salivary glands which secrete it. The structure of
this stomach keeps the food gently moving, and
thereby assists the softening of the food, and the
general action of the saliva. The preparation thus
commenced in the first stomach, enables the food to
pass into the second stomach, and as soon as the
animal is prepared to ruminate the food, or as it is
commonly called, " chew the cud," the food passes
again into the mouth, for the purpose of being more
thoroughly masticated or chewed.
183. This mastication has to accomplish two
distinct objects, it has
To reduce the food into n fine condition, and also
To bring it under the action of the saliva.
It is necessary that the food should be reduced to a
very fine condition, in order that every portion of it
may be the more perfectly acted upon in the process
of digestion. By digestion we mean that action upon
the food, which prepares it for hoing taken up in the
blood,and thus contributing to the growth of the animal.
But this mastication has also the duty of securing
the full action of the saliva upon the food. This
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AGRICULTURE.
[CH.
saliva must not be regarded simply as water which
moistens the food, for it has the power of converting
the starch of food into sugar. This chemical change
is commenced whilst the food is in the first stomach,
and it is materially advanced under the process of
mastication.
184. The food therefore having been gathered in,
softened and fully masticated, when it has thus become
sufficiently soft and sweetened, it is passed into the
third stomach. In the third stomach the food is
simply allowed to macerate or soak for a time, and it
is probable that the starchy matter of the food is here
more completely changed into sugar. The softened
and sweetened food, which is now a semi-fluid mass, is
passed on after a time into the fourth stomach for
further preparation. The first stage is now complete,
for the food has been finely broken up, softened,
and its starchy matter largely turned into
sugar.
185. In the fourth stomach, we find that the
membrane which lines it, has the power of pouring
out, like perspiration on the skin, a liquid which has
been named gastric juice. It is a clear, colour-
less liquid, but with an acid taste, arising from the
presence of hydro-chloric and lactic acids. It also
contains a peculiar organic compound named pepsin.
The gastric j nice has a very strong power of dissolving
the nitrogenous portions of the food, and through its
influence the food undergoes this further change.
The semi-fluid mass is at this stage called the chyme.
This is the second stage in the process of digestion,
and the chyme therefore represents the original food
softened, finely divided, with its starchy matter turned
into Fugar, and the nitrogenous portions of the
food brought into solution.
186. Another stage has to be accomplished, for
in the chyme we have the fatty matter still floating
about as oil, and this has to be prepared fpr being
1
♦>
[CH.
at.]
DIGESTION OF FOOD,
89
taken up by the absorbent vessels. As soon, however,
as the formation of the chyme has been duly perfected,
it is passed from the fourth stomach into the duo-
dejium, which is the highest part of the small intestine,
and here it meets with two other fluids, the bile and
the pancreatic juice. The bile is a secretion
formed by the liver, and is in reality a soap with an
excess of soda. The pancreatic juice is secreted by
the pancreas or sweetbread. This juice is colourless
and transparent, and has the same power as tlie saliva,
for converting any starch into sugar. It is therefore
ready to complete any work left unfinished by the
saliva in the first stage. The bile, however, has
entirely new work to accomplish, viz., getting the
oily mcitter of food blended with water.
187. You know that common soap carries with
it a certain quantity of soda, and if used upon any
greasy matter, it enables the grease to be mixed with
the water used for the purpose of washing, and thus
the oily matter is removed in the water. The bile is
an animal soap, and as soon as it is brought in con-
tact with the oily matter floating in the chyme, the
soda it contains enters into combination, and the oilv
matter of the original food is blended with
the water. After the chyme has been thus acted
upon by the bile it is called chyle, and this associa-
tion of names may help you to remember their proper
sequence.
188. The mineral matter found in food is under the
same conditions, and especially by the action of the
gastric juice, prepared for entering into the circula-
tion, and thus the blood also becomes charged with
the inorganic matter which is required.
189. We have now got each portion of the food
blended with water, viz., the starchy matters of the
food, the nitrogenous substances, the oily portions,
and the inorganic matter. These supplies of food are
always accompanied by other matters, such as cellulose
90
AGRICULTURE.
[CH.
X.]
and woody fibre, which pass away in the excre-
ment, after the useful portions have been separated.
This separation of valuable food materials, is carried
out by a series of absorbent vessels, and being passed
into the blood is conveyed to the lungs where tne
oxidation by the atmospheric air is commenced.
190. We have now arrived at an intermediate stage,
and having introduced the nutriment of food into the
blood, we may indicate its course onwards until made
use of by the animal. Its duty commences in the lungs
and bloodvessels, for in the oxidation which there takes
place, we have carbonic acid largely formed, the tem-
perature of the blood thereby maintained (166), and
the warmth of the animal is provided for. From the
lungs, the blood is pumped by the heart through
arteries, which terminate in beautiful hair-like tubes,
called capillaries. These form a complete network
throughout the body, and they are so generally dis-
tributed that even the prick of a pin reveals their
existence. These capillaries allow the serum of
the blood, which contains the fibrin in solution,
to pass through and exude from them, and when that
matter is brought into contact with living tissue, it is
made use of for its growth. In the same way, the
oily matter in the blood is rendered available for
the growth of fatty tissues.
191. The growth of the body is therefore dependent
upon the food which the animal receives, and upon that
general condition of health, which enables the processes
of digestion and absorption to proceed in a proper
manner. A considerable portion of the food is neces-
sary for the maintenance of the body in a healthy con-
dition, but this does not contribute to its growth.
The warmth of the body must be kept up if the animal
is to be preserved in health, and this necessitates the
use of a certain amount of non-nitrogenous matter,
without any increase of growth. In the same manner
ft? ordjiiarjr w^^te gf the tissues of fte bodj^ rowst l^e
[CH.
X.]
TAX UPON FOOD.
91
restored, and this necessitates the unproductive use of
a certain quantity of nitrogenous matter. It is a sort
of life tax which has to be paid in order that the ani-
mal may be kept in health and strength to perform
some useful duty.
192. In order that some idea may be formed of the
extent to which the elements of food are used for the
maintenance of the body in health, independent of any
production of flesh, we will take the case of a cow in
milk, which received a known quantity of food during
twenty-four hours and (assuming, as may fairly be done,
that she remained the same weight at the end of the
day as at the beginning) disposed of it in the following
manner. The food given consisted of 120 lbs. of
water, 30 lbs. of potatoes, and 15 lbs. of grass. {Bous-
' ', i '■■ !.
Composition
OF THE Food.
COMPOSITION
OF THE Milk.
Composition
OF THE
Dung.
Passed
THROUGH
THE Lungs,
Kidneys,
AND Skin.
Water,
Carbon,
Hydrogen,
Oxygen,
Nitrogen,
Ash,
lbs.
143-92
9-62
118
8 -06
•38
1-84
lbs.
1478
1-25
-20
•64
•09
-II
lbs.
48-83
3-42
-42
301
•18
•96
lbs.
80-31
4*95
•56
4-41
•II
•77
165-
17-07
56-82
9111
In this case we have —
17 lbs. utilized as milk.
'.j/ite
',1'.-. -• ; r 1 ;;, : > i
.d3"W</'l,i^ .r)3 57 lbs. indigestible matter.
f .. ^ . ; .. . ?r • - 01 lbs. the waste of the body. . ; , , , ,
.>iitao?/iV' ' ; J65 lbs. weight of food given, * ■'■'
193. The food which is necessary for supplying
the W?^3te Pf the l?ody is variable, because tb^ m-
u
93
AGRICULTURE.
[CH.
cumstances and conditions which influence the body
are variable. More non-nitrogenous matter is used in
cold weather than when it is warm, and if there be
much exercise taken by the animal, the demand for
nitrogenous matter is increased in proportion. It is,
however, a demand which must be satisfied before the
animal can either make growth, or add any fat to its
body. •]. >^i.'. '- s ;v- .g;/:;- u.a.
194. Our only true foundation for determining the
feeding power of any food, is by the evidence obtained
by experimental trial. The following table shows the
increase in the live weight of the animal, obtained from
the several varieties of food named:
•I ■ , ;' > ; Increase in
live "weight
150 lbs. Swedes consumed in the field . . . gave i lb.
100 ,, Swedes fed in field, with shed to run under ,, i ,,
12 ,, Good clover hay ,, i 1,
8 ,, Beans >> I >i
8 ,, Peas , . , , • , . ,,!,,
7 .. Oats „ I ,,
6 ,, Barley , . ,, i „
5 or 6 ,, Linseed cake n i >>
4^ ,, Linseed cake and peas in equal proportion ,, i ,,
3^ ,, Linseed cake and beans . . . . n i ,1
195. A distinction must be drawn between an
increase in the live weight and an increase
in flesh. The general growth in the body neces-
sitates a development of the digestive organs, and
other parts of the body constituting the offal, as well
as an increase of flesh, bone, and fat. The former
mnst be looked upon as necessary machinery, and the
latter as the product obtained.
In Sheep, 14 lbs. of live weight usually consists of 5 lbs. offal
and 9 lbs. meat.
; In Cattle, 14 lbs. of live weight usually consists of 6 lbs. offal
and 8 lbs. meat. ,
It has been already stated (194) that, under certain
circumstances, 150 lbs. swedes produced i lb. increase
in live weight; therefore, 2,100 lbs, swedes would be
[CH.
body
X.]
SUPPLEMENTAL FOOD.
93
1
equal to 14 lbs. increase in live weight, or 9 lbs. of
mutton.
196. We thus see that food has two drawbacks in
its conversion into meat. It has to pay a life-tax for
maintaining the animal in a healthy condition, and it
has also to construct out of the food the machinery
necessary for the conversion of the residue into meat.
But whilst we fully recognize these unavoidable duties,
they distinctly indicate the economy of making a full
use of the advantages thus purchased. To keep an
animal intended for the production of meat, in such a
manner that it makes no progress, is practically
paying for a privilege which you do not make use of.
If, on the other hand, having paid out of the food
these necessary demands, care be also taken to give
the animal such food as shall promote rapid produc-
tion of meat, you then take advantage of the oppor-
tunity you have purchased.
197. From the same point of view we may also
more fully realize the value of artificial food such as
linseed cake, corn, &c., in acting in a supplemental
capacity. For instance, assuming an animal feeding
upon grass or roots to be receiving therefrom just
sufficient food to keep it from losing weight, the
daily demand of the body will have been thereby
satisfied. If such an animal received some additional
food, it would be able to turn that supplemental
food into a marketable form, with much less
loss of useful material. In the one case the
toll is paid for an empty cart; in the other case
we pass a profitable load. But if a given quantity of
good food were supplied to an animal at a rate not
equal to the waste of the body, then we not only
do not get any increase of live weight for the food
used, but the animal loses weight. In fact, it makes
up the deficiency in the supply by feedmg upon itself,
and if the treatment were continued long enough, the
, nimal would starve for want of a sufficiency o(
94
AGRICULTURE,
[ctt.
Jtl
food. You must therefore fully realize the fact, that
although food is capable of yielding a certain in-
crease of live weight, the result actually obtained
depends in part upon the rate of supply.
198. It was at one time generally considered that
the percentage of nitrogenous, and non -nitrogenous
matter in a food, indicated its powers of producing
flesh and fat respectively. We have proved by experi-
ment the actual feeding powers of different kinds of
food (194), but this does not support the opinion,
that analysis now indicates the quantity of ^esh and fat
which will be produced by a food. If, however, we
know what any food of a given quality will produce,
we may rely with confidence upon an analysis showing
whether any particular sample is likely to produce
larger or smaller results. Analysis is a safe guide for
determining the difference in value between two
samplesof food, sayof linseed cake; but we must rely
upon actual experiment for proving its value as food.
This will be more fully confirmed by the facts stated
in the next paragraph.
^ 1^9. It has been shown by repeated trials that by a
judicious combination of different kinds of food,
we can obtain a much larger production of flesh^nd
fat, than by using the same quantity of the same food
separately from each other. For instance, it has been
stated (194) that 8 lbs. of beans or 6 lbs. of linseed
cake are each capable of producing i lb. of increase
in live weight, but it has also been shown by direct
experiment, that when these foods are mixed and given
together, then we just get double the produce. Thus
8 lbs. of beams would produce one pound increase,
and 6 lbs. of linseed cake would produce a second
pound, but if the beans and linseed cake are given as
a mixed food, they produce 4 lbs. increase of live
weight. In forming an estimate of the results which
are likely to arise from the use of any artificial or
supplemental foodi itmusi therefore be borne in mindi
n
[CH.
M
yUDlClOVS USE OF hOOD,
^
that these results are largely influenced by a judicious
combination of foods possessing different quali«
tieSy the one being essentially a fat-producing food,
(such as linseed cake, linseed, barley, &c.,) and th«
other a flesh-forming food (such as beans, peas, lentiTs,
&c.). It appears as if the growth of flesh and fat took
place more rapidly when the materials are abu7*dant
for both, than when the supplies are limited to that
which is necessary for the one or the other.
200. In this mixture of food, it is desirable to regulate
the proportions in accordance with the age 0? the
animal. If it be a full-grown animal which is being
fattened, less flesh-forming food will be necessary than
if the animal were making great muscular growth. Still
even in such a case a moderate use of flesh-forming
food will be found economical. In the case of a young
and growing animal, in which the growth of muscle
(or flesh) is taking place at the same time as fat is
being formed, the necessity for both is evident. The
successful production of flesh and fat is therefore
dependent upon a proper supply, and a judicious use
of the necessary materials in the food, and upon the
adaptation of the animal system for its ecoDomical
conversion into meat.
1
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